Sniffer troubleshooting: Difference between revisions

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{{DISPLAYTITLE:Troubleshooting: No Calls Being Sniffed}}
= Sniffer Troubleshooting =
[[Category:Troubleshooting]]
[[Category:Sensor]]


'''This guide provides a systematic process to diagnose why the VoIPmonitor sensor might not be capturing any calls. Use it to quickly identify and resolve the most common issues.'''
This page covers common VoIPmonitor sniffer/sensor problems organized by symptom. For configuration reference, see [[Sniffer_configuration]]. For performance tuning, see [[Scaling]].


__TOC__
== Critical First Step: Is Traffic Reaching the Interface? ==


== Quick Diagnostic Flowchart ==
{{Warning|Before any sensor tuning, verify packets are reaching the network interface. If packets aren't there, no amount of sensor configuration will help.}}


Use this flowchart to quickly identify where your problem lies:
<syntaxhighlight lang="bash">
# Check for SIP traffic on the capture interface
tcpdump -i eth0 -nn "host <PROBLEMATIC_IP> and port 5060" -c 10
 
# If no packets: Network/SPAN issue - contact network admin
# If packets visible: Proceed with sensor troubleshooting below
</syntaxhighlight>


<kroki lang="mermaid">
<kroki lang="mermaid">
flowchart TD
graph TD
     A[No Calls in GUI] --> B{Is voipmonitor<br/>service running?}
     A[No Calls Recorded] --> B{Packets on interface?<br/>tcpdump -i eth0 port 5060}
     B -->|No| C[Start service:<br/>systemctl start voipmonitor]
     B -->|No packets| C[Network Issue]
     B -->|Yes| D{Does tshark see<br/>SIP traffic?}
     C --> C1[Check SPAN/mirror config]
     D -->|No| E[Network/Mirror<br/>Configuration Issue]
     C --> C2[Verify VLAN tagging]
     D -->|Yes| F{Check voipmonitor.conf:<br/>interface, sipport, filter}
     C --> C3[Check cable/port]
     F -->|Config OK| G{Check GUI<br/>Capture Rules}
     B -->|Packets visible| D[Sensor Issue]
     G -->|Rules OK| H{Database<br/>connection errors?}
     D --> D1[Check voipmonitor.conf]
     H -->|Yes| I[Fix MySQL connection<br/>in voipmonitor.conf]
     D --> D2[Check GUI Capture Rules]
     H -->|No| J[Check logs for<br/>other errors]
     D --> D3[Check logs for errors]
</kroki>


    E --> E1[Verify SPAN/TAP config]
== Quick Diagnostic Checklist ==
    E --> E2[Check promiscuous mode<br/>for Layer 2 mirrors]


    C --> B
{| class="wikitable"
|-
! Check !! Command !! Expected Result
|-
| Service running || <code>systemctl status voipmonitor</code> || Active (running)
|-
| Traffic on interface || <code>tshark -i eth0 -c 5 -Y "sip"</code> || SIP packets displayed
|-
| Interface errors || <code>ip -s link show eth0</code> || No RX errors/drops
|-
| Promiscuous mode || <code>ip link show eth0</code> || PROMISC flag present
|-
| Logs || <code>tail -100 /var/log/syslog \| grep voip</code> || No critical errors
|-
| GUI rules || Settings → Capture Rules || No unexpected "Skip" rules
|}


    style A fill:#ff6b6b
== No Calls Being Recorded ==
    style C fill:#4ecdc4
    style I fill:#4ecdc4
    style E1 fill:#ffe66d
    style E2 fill:#ffe66d
</kroki>


== Is the VoIPmonitor Service Running Correctly? ==
=== Service Not Running ===
First, confirm the sensor process is active and loaded the correct configuration file.


;1. Check the service status (for modern systemd systems):
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">systemctl status voipmonitor</syntaxhighlight>
# Check status
Look for a line that says <code>Active: active (running)</code>. If it is inactive or failed, try restarting it with <code>systemctl restart voipmonitor</code> and check the status again.
systemctl status voipmonitor


;2. Service Fails to Start with "Binary Not Found" After Crash:
# View recent logs
If the VoIPmonitor service fails to start after a crash or watchdog restart with an error message indicating the binary cannot be found (e.g., "No such file or directory" for <code>/usr/local/sbin/voipmonitor</code>), the binary may have been renamed with an underscore suffix during the crash recovery process.
journalctl -u voipmonitor --since "10 minutes ago"


Check for a renamed binary:
# Start/restart
<syntaxhighlight lang="bash">
systemctl restart voipmonitor
# Check if the standard binary path exists
ls -l /usr/local/sbin/voipmonitor
 
# If not found, look for a renamed version with underscore suffix
ls -l /usr/local/sbin/voipmonitor_*
</syntaxhighlight>
</syntaxhighlight>


If you find a renamed binary (e.g., <code>voipmonitor_</code>, <code>voipmonitor_20250104</code>, etc.), rename it back to the standard name:
Common startup failures:
<syntaxhighlight lang="bash">
* '''Interface not found''': Check <code>interface</code> in voipmonitor.conf matches <code>ip a</code> output
mv /usr/local/sbin/voipmonitor_ /usr/local/sbin/voipmonitor
* '''Port already in use''': Another process using the management port
</syntaxhighlight>
* '''License issue''': Check [[License]] for activation problems


Then restart the service:
=== Wrong Interface or Port Configuration ===
<syntaxhighlight lang="bash">
systemctl start voipmonitor
</syntaxhighlight>


Verify the service starts correctly:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
systemctl status voipmonitor
# Check current config
</syntaxhighlight>
grep -E "^interface|^sipport" /etc/voipmonitor.conf


;3. Sensor Becomes Unresponsive After GUI Update:
# Example correct config:
If the sensor service fails to start or becomes unresponsive after updating a sensor through the Web GUI, the update process may have left the service in a stuck state. The solution is to forcefully stop the service and restart it using these commands:
# interface = eth0
<syntaxhighlight lang="bash">
# sipport = 5060
# SSH into the sensor host and execute:
killall voipmonitor
systemctl stop voipmonitor
systemctl start voipmonitor
</syntaxhighlight>
</syntaxhighlight>
After running these commands, verify the sensor status in the GUI to confirm it is responding correctly. This sequence ensures: (1) Any zombie or hung processes are terminated with <code>killall</code>, (2) systemd is fully stopped, and (3) a clean start of the service.


;4. Verify the running process:
{{Tip|For multiple SIP ports: <code>sipport = 5060,5061,5080</code>}}
<syntaxhighlight lang="bash">ps aux | grep voipmonitor</syntaxhighlight>
This command will show the running process and the exact command line arguments it was started with. Critically, ensure it is using the correct configuration file, for example: <code>--config-file /etc/voipmonitor.conf</code>. If it is not, there may be an issue with your startup script.


== Is Network Traffic Reaching the Server? ==
=== GUI Capture Rules Blocking ===
If the service is running, verify if the VoIP packets (SIP/RTP) are actually arriving at the server's network interface. The best tool for this is <code>tshark</code> (the command-line version of Wireshark).


;1. Install tshark:
Navigate to '''Settings → Capture Rules''' and check for rules with action "Skip" that may be blocking calls. Rules are processed in order - a Skip rule early in the list will block matching calls.
<syntaxhighlight lang="bash">
# For Debian/Ubuntu
apt-get update && apt-get install tshark


# For CentOS/RHEL/AlmaLinux
See [[Capture_rules]] for detailed configuration.
yum install wireshark
</syntaxhighlight>
 
;2. Listen for SIP traffic on the correct interface:
Replace <code>eth0</code> with the interface name you have configured in <code>voipmonitor.conf</code>.
<syntaxhighlight lang="bash">
tshark -i eth0 -Y "sip || rtp" -n
</syntaxhighlight>
* '''If you see a continuous stream of SIP and RTP packets''', it means traffic is reaching the server, and the problem is likely in VoIPmonitor's configuration (see [[#Check the VoIPmonitor Configuration|Check the VoIPmonitor Configuration]]).
* '''If you see NO packets''', the problem lies with your network configuration. See [[#Troubleshoot Network and Interface Configuration|Troubleshoot Network and Interface Configuration]].


;3. Advanced: Capture to PCAP File for Definitive Testing
=== SPAN/Mirror Not Configured ===
Live monitoring with tshark is useful for observation, but capturing traffic to a .pcap file during a test call provides definitive evidence for troubleshooting intermittent issues or specific call legs.


'''Method 1: Using tcpdump (Recommended)'''
If <code>tcpdump</code> shows no traffic:
<syntaxhighlight lang="bash">
# Verify switch SPAN/mirror port configuration
# Start capture on the correct interface (replace eth0)
# Check that both directions (ingress + egress) are mirrored
tcpdump -i eth0 -s 0 -w /tmp/test_capture.pcap port 5060
# Confirm VLAN tagging is preserved if needed
# Test physical connectivity (cable, port status)


# Or capture both SIP and RTP traffic:
See [[Sniffing_modes]] for SPAN, RSPAN, and ERSPAN configuration.
tcpdump -i eth0 -s 0 -w /tmp/test_capture.pcap "(port 5060 or udp)"


# Let it run while you make a test call with the missing call leg
=== Filter Parameter Too Restrictive ===
# Press Ctrl+C to stop the capture


# Analyze the capture file:
If <code>filter</code> is set in voipmonitor.conf, it may exclude traffic:
tshark -r /tmp/test_capture.pcap -Y "sip"
</syntaxhighlight>


'''Method 2: Using tshark to capture to file'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Start capture:
# Check filter
tshark -i eth0 -w /tmp/test_capture.pcap -f "tcp port 5060 or udp"
grep "^filter" /etc/voipmonitor.conf


# Make your test call, then press Ctrl+C to stop
# Temporarily disable to test
# Comment out the filter line and restart
</syntaxhighlight>


# Analyze the capture:
tshark -r /tmp/test_capture.pcap -Y "sip" -V
</syntaxhighlight>


'''Decision Tree for PCAP Analysis:'''


After capturing a test call known to have a missing leg:
==== Missing id_sensor Parameter ====


* '''If SIP packets are missing from the .pcap file:'''
'''Symptom''': SIP packets visible in Capture/PCAP section but missing from CDR, SIP messages, and Call flow.
** The problem is with your network mirroring configuration (SPAN/TAP port, AWS Traffic Mirroring, etc.)
** The packets never reached the VoIPmonitor sensor's network interface
** Fix the switch mirroring setup or infrastructure configuration first


* '''If SIP packets ARE present in the .pcap file but missing in the VoIPmonitor GUI:'''
'''Cause''': The <code>id_sensor</code> parameter is not configured or is missing. This parameter is required to associate captured packets with the CDR database.
** The problem is with VoIPmonitor's configuration or processing
** Packets reached the NIC but were not processed correctly
** Review [[#Check the VoIPmonitor Configuration|VoIPmonitor Configuration]] and [[#Check GUI Capture Rules (Causing Call Stops)|Capture Rules]]


'''Example Test Call Workflow:'''
'''Solution''':
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# 1. Start capture
# Check if id_sensor is set
tcpdump -i eth0 -s 0 -w /tmp/test.pcap "port 5060 and host 10.0.1.100"
grep "^id_sensor" /etc/voipmonitor.conf


# 2. Make a test call from phone at 10.0.1.100 to 10.0.2.200
# Add or correct the parameter
#    (a call that you know should have recordings but is missing)
echo "id_sensor = 1" >> /etc/voipmonitor.conf


# 3. Stop capture (Ctrl+C)
# Restart the service
 
systemctl restart voipmonitor
# 4. Check for the specific call's Call-ID
tshark -r /tmp/test.pcap -Y "sip" -T fields -e sip.Call-ID
 
# 5. Verify if packets for both A-leg and B-leg exist
tshark -r /tmp/test.pcap -Y "sip && ip.addr == 10.0.1.100"
 
# 6. Compare results with VoIPmonitor GUI
#    - If packets found in .pcap: VoIPmonitor software issue
#    - If packets missing from .pcap: Network mirroring issue
</syntaxhighlight>
</syntaxhighlight>


== Check Sensor Statistics in GUI ==
{{Tip|Use a unique numeric identifier (1-65535) for each sensor. Essential for multi-sensor deployments. See [[Sniffer_configuration#id_sensor|id_sensor documentation]].}}
If <code>tshark</code> confirms traffic is reaching the interface, use the VoIPmonitor GUI to verify the sensor is processing packets without drops.
== Missing Audio / RTP Issues ==


;1. Navigate to '''Settings → Sensors'''
=== One-Way Audio (Asymmetric Mirroring) ===
:Expand the sensor details to view real-time capture statistics.


;2. Check the '''# packet drops''' counter:
'''Symptom''': SIP recorded but only one RTP direction captured.
:This counter should ideally be '''0'''. If it shows a value other than zero, the sensor is dropping packets due to processing bottlenecks, insufficient buffer memory, or hardware limitations.


;3. Common causes of packet drops:
'''Cause''': SPAN port configured for only one direction.
{| class="wikitable"
|-
! Symptom !! Likely Cause !! Solution
|-
| Drops increase with high traffic | Insufficient buffer memory | Increase <code>ringbuffer</code> or <code>max_buffer_mem</code> in <code>voipmonitor.conf</code><br/>See [[Scaling]] for tuning guidance
|-
| Consistent drops at moderate traffic | CPU bottleneck | Check sensor CPU utilization; consider dedicating cores with <code>cpu_affinity</code>
|-
| Drops only on specific interfaces | Hardware/driver issue | Verify interface driver; check for errors with <code>ethtool -S eth0</code>
|-
| Drops after configuration change | New filter or feature overload | Remove or simplify BPF filters, disable unnecessary features
|}


;4. Other useful sensor statistics:
'''Diagnosis''':
{| class="wikitable"
<syntaxhighlight lang="bash">
|-
# Count RTP packets per direction
! Metric !! Description
tshark -i eth0 -Y "rtp" -T fields -e ip.src -e ip.dst | sort | uniq -c
|-
</syntaxhighlight>
| '''Packets/sec''' | Current capture rate
|-
| '''Bytes/sec''' | Current bandwidth utilization
|-
| '''Calls/sec''' | Call processing rate
|-
| '''Graph''' | Real-time graph of capture rates over time
|}


For detailed performance metrics beyond basic statistics, see [[Understanding_the_Sniffer's_Performance_Log]].
If one direction shows 0 or very few packets, configure the switch to mirror both ingress and egress traffic.


== Troubleshoot Network and Interface Configuration ==
=== RTP Not Associated with Call ===
If <code>tshark</code> shows no traffic, it means the packets are not being delivered to the operating system correctly.


;1. Check if the interface is UP:
'''Symptom''': Audio plays in sniffer but not in GUI, or RTP listed under wrong call.
Ensure the network interface is active.
<syntaxhighlight lang="bash">ip link show eth0</syntaxhighlight>
The output should contain the word <code>UP</code>. If it doesn't, bring it up with:
<syntaxhighlight lang="bash">ip link set dev eth0 up</syntaxhighlight>


;2. Check for Promiscuous Mode (for SPAN/RSPAN Mirrored Traffic):
'''Possible causes''':
'''Important:''' Promiscuous mode requirements depend on your traffic mirroring method:


{| class="wikitable"
'''1. SIP and RTP on different interfaces/VLANs''':
|-
<syntaxhighlight lang="ini">
! Mirroring Method !! Promiscuous Mode Required? !! Reason
# voipmonitor.conf - enable automatic RTP association
|-
auto_enable_use_blocks = yes
| SPAN/RSPAN (Layer 2) || '''Yes''' || Mirrored packets retain original MAC addresses; interface must accept all packets
</syntaxhighlight>
|-
| ERSPAN/GRE/TZSP/VXLAN (Layer 3) || '''No''' || Tunneled traffic is addressed directly to sensor's IP; VoIPmonitor decapsulates automatically
|}


For SPAN/RSPAN deployments, check the current promiscuous mode status:
'''2. NAT not configured''':
<syntaxhighlight lang="bash">ip link show eth0</syntaxhighlight>
<syntaxhighlight lang="ini">
Look for the <code>PROMISC</code> flag.
# voipmonitor.conf - for NAT scenarios
natalias = <public_ip> <private_ip>


Enable promiscuous mode manually if needed:
# If not working, try reversed order:
<syntaxhighlight lang="bash">ip link set eth0 promisc on</syntaxhighlight>
natalias = <private_ip> <public_ip>
If this solves the problem, you should make the change permanent. The <code>install-script.sh</code> for the sensor usually attempts to do this, but it can fail.
</syntaxhighlight>


;3. Verify Your SPAN/Mirror/TAP Configuration:
'''3. External device modifying media ports''':
This is the most common cause of no traffic. Double-check your network switch or hardware tap configuration to ensure:
* The correct source ports (where your PBX/SBC is connected) are being monitored.
* The correct destination port (where your VoIPmonitor sensor is connected) is configured.
* If you are monitoring traffic across different VLANs, ensure your mirror port is configured to carry all necessary VLAN tags (often called "trunk" mode).


== Check the VoIPmonitor Configuration ==
If SDP advertises one port but RTP arrives on different port (SBC/media server issue):
If <code>tshark</code> sees traffic but VoIPmonitor does not, the problem is almost certainly in <code>voipmonitor.conf</code>.
<syntaxhighlight lang="bash">
# Compare SDP ports vs actual RTP
tshark -r call.pcap -Y "sip.Method == INVITE" -V | grep "m=audio"
tshark -r call.pcap -Y "rtp" -T fields -e udp.dstport | sort -u
</syntaxhighlight>


;1. Check the <code>interface</code> directive:
If ports don't match, the external device must be configured to preserve SDP ports - VoIPmonitor cannot compensate.
:Make sure the <code>interface</code> parameter in <code>/etc/voipmonitor.conf</code> exactly matches the interface where you see traffic with <code>tshark</code>. For example: <code>interface = eth0</code>.
=== RTP Incorrectly Associated with Wrong Call (PBX Port Reuse) ===
'''Symptom''': RTP streams from one call appear associated with a different CDR when your PBX aggressively reuses the same IP:port across multiple calls.


;2. Check the <code>sipport</code> directive:
'''Cause''': When PBX reuses media ports, VoIPmonitor may incorrectly correlate RTP packets to the wrong call based on weaker correlation methods.
:By default, VoIPmonitor only listens on port 5060. If your PBX uses a different port for SIP, you must add it. For example:
:<code>sipport = 5060,5080</code>


;3. Check for a restrictive <code>filter</code>:
'''Solution''': Enable <code>rtp_check_both_sides_by_sdp</code> to require verification of both source and destination IP:port against SDP:
:If you have a BPF <code>filter</code> configured, ensure it is not accidentally excluding the traffic you want to see. For debugging, try commenting out the <code>filter</code> line entirely and restarting the sensor.
<syntaxhighlight lang="ini">
# voipmonitor.conf - require both source and destination to match SDP
rtp_check_both_sides_by_sdp = yes


== Check GUI Capture Rules (Causing Call Stops) ==
# Alternative (strict) mode - allows initial unverified packets
If <code>tshark</code> sees SIP traffic and the sniffer configuration appears correct, but the probe stops processing calls or shows traffic only on the network interface, GUI capture rules may be the culprit.
rtp_check_both_sides_by_sdp = strict
</syntaxhighlight>


Capture rules configured in the GUI can instruct the sniffer to ignore ("skip") all processing for matched calls. This includes calls matching specific IP addresses or telephone number prefixes.
{{Warning|Enabling this may prevent RTP association for calls using NAT, as the source IP:port will not match the SDP. Use <code>natalias</code> mappings or the <code>strict</code> setting to mitigate this.}}
=== Snaplen Truncation ===


;1. Review existing capture rules:
'''Symptom''': Large SIP messages truncated, incomplete headers.
:Navigate to '''GUI → Capture rules''' and examine all rules for any that might be blocking your traffic.
:Look specifically for rules with the '''Skip''' option set to '''ON''' (displayed as "Skip: ON"). The Skip option instructs the sniffer to completely ignore matching calls (no files, RTP analysis, or CDR creation).


;2. Test by temporarily removing all capture rules:
'''Solution''':
:To isolate the issue, first create a backup of your GUI configuration:
<syntaxhighlight lang="ini">
:* Navigate to '''Tools → Backup & Restore → Backup GUI → Configuration tables'''
# voipmonitor.conf - increase packet capture size
:* This saves your current settings including capture rules
snaplen = 8192
:* Delete all capture rules from the GUI
</syntaxhighlight>
:* Click the '''Apply''' button to save changes
:* Reload the sniffer by clicking the green '''"reload sniffer"''' button in the control panel
:* Test if calls are now being processed correctly
:* If resolved, restore the configuration from the backup and systematically investigate the rules to identify the problematic one


;3. Identify the problematic rule:
For Kamailio siptrace, also check <code>trace_msg_fragment_size</code> in Kamailio config. See [[Sniffer_configuration#snaplen|snaplen documentation]].
:* After restoring your configuration, remove rules one at a time and reload the sniffer after each removal
:* When calls start being processed again, you have identified the problematic rule
:* Review the rule's match criteria (IP addresses, prefixes, direction) against your actual traffic pattern
:* Adjust the rule's conditions or Skip setting as needed


;4. Verify rules are reloaded:
== PACKETBUFFER Saturation ==
:After making changes to capture rules, remember that changes are '''not automatically applied''' to the running sniffer. You must click the '''"reload sniffer"''' button in the control panel, or the rules will continue using the previous configuration.


For more information on capture rules, see [[Capture_rules]].
'''Symptom''': Log shows <code>PACKETBUFFER: memory is FULL</code>, truncated RTP recordings.


== Troubleshoot Missing or One-Way Audio ==
{{Warning|This alert refers to VoIPmonitor's '''internal packet buffer''' (<code>max_buffer_mem</code>), '''NOT system RAM'''. High system memory availability does not prevent this error. The root cause is always a downstream bottleneck (disk I/O or CPU) preventing packets from being processed fast enough.}}


If calls are being captured (you see them in the GUI CDR list), but audio is missing or only present in one direction, this indicates an RTP correlation issue. This is different from "no calls being captured" - the problem is specifically that VoIPmonitor cannot link RTP packets to the SIP call.
'''Before testing solutions''', gather diagnostic data:
* Check sensor logs: <code>/var/log/syslog</code> (Debian/Ubuntu) or <code>/var/log/messages</code> (RHEL/CentOS)
* Generate debug log via GUI: '''Tools → Generate debug log'''


'''Symptom:''' CDR shows "No audio" or audio in only one column (Caller/Called), but tshark confirms RTP packets are present on the network.
=== Diagnose: I/O vs CPU Bottleneck ===


=== Step 1: Verify RTP Capture is Enabled ===
{{Warning|Do not guess the bottleneck source. Use proper diagnostics first to identify whether the issue is disk I/O, CPU, or database-related. Disabling storage as a test is valid but should be used to '''confirm''' findings, not as the primary diagnostic method.}}


First, ensure the sensor is configured to save RTP packets.
==== Step 1: Check IO[] Metrics (v2026.01.3+) ====


;1. Check <code>savertp</code> in <code>voipmonitor.conf</code>:
'''Starting with version 2026.01.3''', VoIPmonitor includes built-in disk I/O monitoring that directly shows disk saturation status:
<syntaxhighlight lang="ini">
# Verify RTP saving is enabled
savertp = yes


# Common mistake: savertp=no or savertp=header (saves only headers, not audio)
<syntaxhighlight lang="text">
# For audio recording, savertp must be 'yes'
[283.4/283.4Mb/s] IO[B1.1|L0.7|U45|C75|W125|R10|WI1.2k|RI0.5k]
</syntaxhighlight>
</syntaxhighlight>


;2. Check <code>savesip</code> is also enabled:
'''Quick interpretation:'''
<syntaxhighlight lang="ini">
{| class="wikitable"
# SIP data is required to link RTP to calls
|-
savesip = yes
! Metric !! Meaning !! Problem Indicator
|-
| '''C''' (Capacity) || % of disk's sustainable throughput used || '''C ≥ 80% = Warning''', '''C ≥ 95% = Saturated'''
|-
| '''L''' (Latency) || Current write latency in ms || '''L ≥ 3× B''' (baseline) = Saturated
|-
| '''U''' (Utilization) || % time disk is busy || '''U > 90%''' = Disk at limit
|}
 
'''If you see <code>DISK_SAT</code> or <code>WARN</code> after IO[]:'''
<syntaxhighlight lang="text">
IO[B1.1|L8.5|U98|C97|W890|R5|WI12.5k|RI0.1k] DISK_SAT
</syntaxhighlight>
</syntaxhighlight>


;3. Restart the sniffer after changes:
→ This confirms I/O bottleneck. Skip to [[#Solution:_I.2FO_Bottleneck|I/O Bottleneck Solutions]].
<syntaxhighlight lang="bash">systemctl restart voipmonitor</syntaxhighlight>


=== Step 2: Verify RTP Traffic is Present ===
'''For older versions or additional confirmation''', continue with the steps below.


If <code>savertp = yes</code> but you still have no audio, verify RTP packets are reaching the interface and are actually being processed, not just present in tshark.
{{Note|See [[Syslog_Status_Line#IO.5B....5D_-_Disk_I.2FO_Monitoring_.28v2026.01.3.2B.29|Syslog Status Line - IO[] section]] for detailed field descriptions.}}


<syntaxhighlight lang="bash">
==== Step 2: Read the Full Syslog Status Line ====
# Capture SIP and RTP for a test call
tcpdump -i eth0 -n -w /tmp/test_audio.pcap "sip or udp"


# Make a test call, then analyze:
VoIPmonitor outputs a status line every 10 seconds. This is your first diagnostic tool:
tshark -r /tmp/test_audio.pcap -Y "rtp" -c 10


# Check what ports RTP is using
<syntaxhighlight lang="bash">
tshark -r /tmp/test_audio.pcap -Y "rtp" -T fields -e rtp.ssrc -e udp.srcport -e udp.dstport | head -20
# Monitor in real-time
journalctl -u voipmonitor -f
# or
tail -f /var/log/syslog | grep voipmonitor
</syntaxhighlight>
</syntaxhighlight>


* '''If you see NO RTP packets in the capture:''' The network mirroring is not configured to capture UDP/RTP traffic (common in VLAN-based deployments).
'''Example status line:'''
* '''If you see RTP packets:''' Proceed to Step 3 for correlation troubleshooting.
<syntaxhighlight lang="text">
calls[424] PS[C:4 S:41 R:13540] SQLq[C:0 M:0] heap[45|30|20] comp[48] [25.6Mb/s] t0CPU[85%] t1CPU[12%] t2CPU[8%] tacCPU[8|8|7|7%] RSS/VSZ[365|1640]MB
</syntaxhighlight>


=== Step 3: Diagnose RTP Correlation Failure ===
'''Key metrics for bottleneck identification:'''


VoIPmonitor uses SDP (Session Description Protocol) information in SIP messages to associate RTP packets with calls. If this correlation fails, audio will not be displayed even though RTP packets are captured.
{| class="wikitable"
|-
! Metric !! What It Indicates !! I/O Bottleneck Sign !! CPU Bottleneck Sign
|-
| <code>heap[A&#124;B&#124;C]</code> || Buffer fill % (primary / secondary / processing) || High A with low t0CPU || High A with high t0CPU
|-
| <code>t0CPU[X%]</code> || Packet capture thread (single-core, cannot parallelize) || Low (<50%) || High (>80%)
|-
| <code>comp[X]</code> || Active compression threads || Very high (maxed out) || Normal
|-
| <code>SQLq[C:X M:Y]</code> || Pending SQL queries || Growing = database bottleneck || Stable
|-
| <code>tacCPU[...]</code> || TAR compression threads || All near 100% = compression bottleneck || Normal
|}


The most common causes are:
'''Interpretation flowchart:'''
* NAT devices mismatching IP addresses (SDP shows private IP, RTP arrives from public IP)
* SBCs/media servers modifying RTP ports (SDP advertises port X, RTP arrives on port Y)
* Proxies separating SIP signaling from RTP media path


=== Step 4: Configure NAT Aliases (natalias) ===
<kroki lang="mermaid">
graph TD
    A[heap values rising] --> B{Check t0CPU}
    B -->|t0CPU > 80%| C[CPU Bottleneck]
    B -->|t0CPU < 50%| D{Check comp and tacCPU}
    D -->|comp maxed, tacCPU high| E[I/O Bottleneck<br/>Disk cannot keep up with writes]
    D -->|comp normal| F{Check SQLq}
    F -->|SQLq growing| G[Database Bottleneck]
    F -->|SQLq stable| H[Mixed/Other Issue]


If endpoints are behind NAT, the SDP messages may contain private IPs (e.g., `10.x.x.x`, `192.168.x.x`) but RTP arrives from the firewall's public IP. You must explicitly map these IPs.
    C --> C1[Solution: CPU optimization]
    E --> E1[Solution: Faster storage]
    G --> G1[Solution: MySQL tuning]
</kroki>


;1. Verify correct <code>natalias</code> syntax:
==== Step 3: Linux I/O Diagnostics ====
<syntaxhighlight lang="ini">
# Syntax: natalias = <public_ip> <private_ip>
# OR: natalias = <private_ip> <public_ip>
# Use only TWO parameters (IP addresses, not CIDR notation for simple mappings)


# Example: Map firewall public IP to internal subnet
Use these standard Linux tools to confirm I/O bottleneck:
natalias = 203.0.113.5 10.0.0.50
</syntaxhighlight>


Multiple <code>natalias</code> lines can be used for multiple mappings.
'''Install required tools:'''
<syntaxhighlight lang="bash">
# Debian/Ubuntu
apt install sysstat iotop ioping


;2. Try reversing IP order if initial configuration does not work:
# CentOS/RHEL
<syntaxhighlight lang="ini">
yum install sysstat iotop ioping
# If configuration above doesn't fix issue, try the reverse order:
natalias = 10.0.0.50 203.0.113.5
</syntaxhighlight>
</syntaxhighlight>


This is a common troubleshooting step - the correct order depends on whether RTP is being received from the public IP (typical) or the private IP (after NAT traversal).
'''2a) iostat - Disk utilization and wait times'''
 
<syntaxhighlight lang="bash">
;3. Enable automatic RTP endpoint detection:
# Run for 10 intervals of 2 seconds
<syntaxhighlight lang="ini">
iostat -xz 2 10
# Helps identify actual RTP endpoints behind proxies/NAT
rtpip_find_endpoints = yes
</syntaxhighlight>
</syntaxhighlight>


;4. Relax strict RTP source checking:
'''Key output columns:'''
<syntaxhighlight lang="ini">
<syntaxhighlight lang="text">
# Accept RTP even if source IP differs from SIP header IP
Device  r/s    w/s  rkB/s  wkB/s  await  %util
rtpfromsdp_onlysip = no
sda    12.50  245.30  50.00  1962.40  45.23  98.50
</syntaxhighlight>
</syntaxhighlight>


;5. Restart the sniffer after changes:
{| class="wikitable"
<syntaxhighlight lang="bash">systemctl restart voipmonitor</syntaxhighlight>
|-
! Column !! Description !! Problem Indicator
|-
| <code>%util</code> || Device utilization percentage || '''> 90%''' = disk saturated
|-
| <code>await</code> || Average I/O wait time (ms) || '''> 20ms''' for SSD, '''> 50ms''' for HDD = high latency
|-
| <code>w/s</code> || Writes per second || Compare with disk's rated IOPS
|}


For more configuration options, see [[Sniffer_configuration#NAT_Handling]].
'''2b) iotop - Per-process I/O usage'''
<syntaxhighlight lang="bash">
# Show I/O by process (run as root)
iotop -o
</syntaxhighlight>


=== Step 5: Perform Port Mismatch Analysis ===
Look for <code>voipmonitor</code> or <code>mysqld</code> dominating I/O. If voipmonitor shows high DISK WRITE but system <code>%util</code> is 100%, disk cannot keep up.


If <code>natalias</code> fixes do not resolve the issue, an external device (SBC, media server) may be modifying the RTP ports. This is a common scenario in carrier environments.
'''2c) ioping - Quick latency check'''
<syntaxhighlight lang="bash">
# Test latency on VoIPmonitor spool directory
cd /var/spool/voipmonitor
ioping -c 20 .
</syntaxhighlight>


;1. Capture a test call with both SIP and RTP:
'''Expected results:'''
<syntaxhighlight lang="bash">
{| class="wikitable"
# Start capture
|-
tcpdump -i eth0 -n -w /tmp/port_mismatch.pcap "sip or udp"
! Storage Type !! Healthy Latency !! Problem Indicator
|-
| NVMe SSD || < 0.5 ms || > 2 ms
|-
| SATA SSD || < 1 ms || > 5 ms
|-
| HDD (7200 RPM) || < 10 ms || > 30 ms
|}


# Make a test call with missing audio
==== Step 4: Linux CPU Diagnostics ====
# Press Ctrl+C to stop
</syntaxhighlight>


;2. Extract SDP-advertised RTP ports from SIP:
'''3a) top - Overall CPU usage'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Find INVITE and extract Call-ID
# Press '1' to show per-core CPU
tshark -r /tmp/port_mismatch.pcap -Y "sip.Method == INVITE" -T fields -e sip.Call-ID -e sip.to.user
top
 
# For a specific Call-ID, show SDP port information
tshark -r /tmp/port_mismatch.pcap -Y "sip and sip.Call-ID == YOUR_CALL_ID" -T fields -e sdp.media.port | head -20
</syntaxhighlight>
</syntaxhighlight>


This shows what ports the SIP SDP says RTP should use.
Look for:
* Individual CPU core at 100% (t0 thread is single-threaded)
* High <code>%wa</code> (I/O wait) vs high <code>%us/%sy</code> (CPU-bound)


;3. Extract actual RTP ports from captured packets:
'''3b) Verify voipmonitor threads'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Show all RTP packets and their ports
# Show voipmonitor threads with CPU usage
tshark -r /tmp/port_mismatch.pcap -Y "rtp" -T fields -e rtp.ssrc -e udp.srcport -e udp.dstport -e ip.src -e ip.dst | sort -u | head -20
top -H -p $(pgrep voipmonitor)
</syntaxhighlight>
</syntaxhighlight>


This shows what ports RTP is actually using in the capture.
If one thread shows ~100% CPU while others are low, you have a CPU bottleneck on the capture thread (t0).


;4. Compare the results:
==== Step 5: Decision Matrix ====


{| class="wikitable"
{| class="wikitable"
|-
|-
! Source !! SDP Port (from SIP) !! Actual RTP Port !! Match?
! Observation !! Likely Cause !! Go To
|-
|-
| Example | 50100 | 32456 | '''NO - Port mismatch'''
| <code>heap</code> high, <code>t0CPU</code> > 80%, iostat <code>%util</code> low || '''CPU Bottleneck''' || [[#Solution: CPU Bottleneck|CPU Solution]]
|-
| <code>heap</code> high, <code>t0CPU</code> < 50%, iostat <code>%util</code> > 90% || '''I/O Bottleneck''' || [[#Solution: I/O Bottleneck|I/O Solution]]
|-
| <code>heap</code> high, <code>t0CPU</code> < 50%, iostat <code>%util</code> < 50%, <code>SQLq</code> growing || '''Database Bottleneck''' || [[#SQL Queue Overload|Database Solution]]
|-
| <code>heap</code> normal, <code>comp</code> maxed, <code>tacCPU</code> all ~100% || '''Compression Bottleneck''' (type of I/O) || [[#Solution: I/O Bottleneck|I/O Solution]]
|}
|}


* '''If ports MATCH''': The issue is not port modification. Check NAT configuration again or verify <code>savertp</code> is enabled.
==== Step 6: Confirmation Test (Optional) ====
* '''If ports DO NOT MATCH''': An external device is modifying the media ports.


=== Step 6: External Device Root Cause ===
After identifying the likely cause with the tools above, you can confirm with a storage disable test:


If a port mismatch is detected (Step 5), the root cause is an external device (SBC, media server, SIP proxy) modifying the RTP ports.
<syntaxhighlight lang="ini">
# /etc/voipmonitor.conf - temporarily disable all storage
savesip = no
savertp = no
savertcp = no
savegraph = no
</syntaxhighlight>


'''Important:''' VoIPmonitor requires the SDP-advertised ports to match the actual RTP packet ports for proper correlation. If these do not match, fixing the issue requires changing the configuration of the external device, not VoIPmonitor.
<syntaxhighlight lang="bash">
systemctl restart voipmonitor
# Monitor for 5-10 minutes during peak traffic
journalctl -u voipmonitor -f | grep heap
</syntaxhighlight>


Common external devices that modify RTP ports:
* If <code>heap</code> values drop to near zero → confirms '''I/O bottleneck'''
* Session Border Controllers (SBC)
* If <code>heap</code> values remain high → confirms '''CPU bottleneck'''
* Media servers
* SIP proxies with media handling
* IP-PBX systems with built-in NAT traversal


'''Solutions:'''
{{Warning|Remember to re-enable storage after testing! This test causes call recordings to be lost.}}
1. Check the external device's configuration for media port handling
2. If possible, disable port modification on the external device
3. Use media mirroring features (e.g., Ribbon SBC Monitoring Profile) if available
4. Consider deploying a dedicated sensor on the internal network side where SDP and RTP ports match


For example documentation on SBC mirroring, see [[Ribbon7k_monitoring_profiles]].
=== Solution: I/O Bottleneck ===


=== Step 7: Distributed Architecture Check ===
{{Note|If you see <code>IO[...] DISK_SAT</code> or <code>WARN</code> in the syslog status line (v2026.01.3+), disk saturation is already confirmed. See [[Syslog_Status_Line#IO.5B....5D_-_Disk_I.2FO_Monitoring_.28v2026.01.3.2B.29|IO[] Metrics]] for details.}}


VoIPmonitor cannot associate SIP and RTP if they are captured by different sensors.
'''Quick confirmation (for older versions):'''


;Scenario:*
Temporarily save only RTP headers to reduce disk write load:
* Sensor A captures SIP traffic (VLAN 10)
<syntaxhighlight lang="ini">
* Sensor B captures RTP traffic (VLAN 20)
# /etc/voipmonitor.conf
* Both sensors send data to the same GUI
savertp = header
</syntaxhighlight>


;Result:* The GUI cannot reconstruct the call because SIP and RTP are not on the same sensor.
Restart the sniffer and monitor. If heap usage stabilizes and "MEMORY IS FULL" errors stop, the issue is confirmed to be storage I/O.


;Solution:*
'''Check storage health before upgrading:'''
* Ensure one single sensor instance sees both SIP signaling and RTP media
<syntaxhighlight lang="bash">
* Use a trunk port in the switch mirror configuration
# Check drive health
* Or use a combined mode where all traffic goes to one interface
smartctl -a /dev/sda


For more details, see [[Sniffer_distributed_architecture]].
# Check for I/O errors in system logs
dmesg | grep -i "i/o error\|sd.*error\|ata.*error"
</syntaxhighlight>


=== Quick Decision Matrix ===
Look for reallocated sectors, pending sectors, or I/O errors. Replace failing drives before considering upgrades.


'''Storage controller cache settings:'''
{| class="wikitable"
{| class="wikitable"
|-
|-
! Symptom !! Likely Cause !! Primary Solution
! Storage Type !! Recommended Cache Mode
|-
| tshark shows NO RTP traffic | Network Mirroring/VLANs | Fix SPAN/TAP or allow VLAN trunk
|-
| tshark shows RTP, GUI shows "No audio" | <code>savertp ≠ yes</code> | Set <code>savertp = yes</code>
|-
| tshark shows RTP, GUI shows one-way audio | NAT/Proxy correlation failure | Enable <code>rtpip_find_endpoints</code> and <code>natalias</code>
|-
|-
| SDP and RTP ports do not match | External device modifying ports | Fix SBC/media server configuration
| HDD / NAS || WriteBack (requires battery-backed cache)
|-
|-
| SIP on sensor A, RTP on sensor B | Distributed architecture issue | Capture both on single sensor
| SSD || WriteThrough (or WriteBack with power loss protection)
|}
|}


== Troubleshoot MySQL/MariaDB Database Connection Errors ==
Use vendor-specific tools to configure cache policy (<code>megacli</code>, <code>ssacli</code>, <code>perccli</code>).
If you see "Connection refused (111)" errors or the sensor cannot connect to your database server, the issue is with the MySQL/MariaDB database connection configuration in <code>/etc/voipmonitor.conf</code>.
 
Error 111 (Connection refused) indicates that the database server is reachable on the network, but no MySQL/MariaDB service is listening on the specified port, or the connection is being blocked by a firewall. This commonly happens after migrations when the database server IP address has changed.
 
=== Symptoms and Common Errors ===


'''Storage upgrades (in order of effectiveness):'''
{| class="wikitable"
{| class="wikitable"
|-
|-
! Error Message !! Likely Cause
! Solution !! IOPS Improvement !! Notes
|-
|-
| <code>Can't connect to MySQL server on 'IP' (111)</code> || Wrong host/port or service not running
| '''NVMe SSD''' || 50-100x vs HDD || Best option, handles 10,000+ concurrent calls
|-
|-
| <code>Access denied for user 'user'@'host'</code> || Wrong username or password
| '''SATA SSD''' || 20-50x vs HDD || Good option, handles 5,000+ concurrent calls
|-
|-
| <code>Unknown database 'voipmonitor'</code> || Wrong database name
| '''RAID 10 with BBU''' || 5-10x vs single disk || Enable WriteBack cache (requires battery backup)
|-
| '''Separate storage server''' || Variable || Use [[Sniffer_distributed_architecture|client/server mode]]
|}
|}


=== Diagnostic Steps ===
'''Filesystem tuning (ext4):'''
 
;1. Check for database connection errors in sensor logs:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# For Debian/Ubuntu (systemd journal)
# Check current mount options
journalctl -u voipmonitor --since "1 hour ago" | grep -iE "mysql|database|connection|can.t connect"
mount | grep voipmonitor


# For systems using traditional syslog
# Recommended mount options for /var/spool/voipmonitor
tail -f /var/log/syslog | grep voipmonitor | grep -iE "mysql|database|connection"
# Add to /etc/fstab: noatime,data=writeback,barrier=0
 
# WARNING: barrier=0 requires battery-backed RAID
# For CentOS/RHEL/AlmaLinux
tail -f /var/log/messages | grep voipmonitor | grep -iE "mysql|database|connection"
</syntaxhighlight>
</syntaxhighlight>


;2. Verify database connection parameters in <code>voipmonitor.conf</code>:
'''Verify improvement:'''
<syntaxhighlight lang="ini">
<syntaxhighlight lang="bash">
# Database Connection Parameters
# After changes, monitor iostat
mysqlhost = 192.168.1.10       # IP address or hostname of MySQL/MariaDB server
iostat -xz 2 10
mysqlport = 3306              # TCP port of the database server (default: 3306)
# %util should drop below 70%, await should decrease
mysqlusername = root          # Database username
mysqlpassword = your_password  # Database password
mysqldatabase = voipmonitor    # Database name
</syntaxhighlight>
</syntaxhighlight>


;3. Test MySQL connectivity from the sensor host:
=== Solution: CPU Bottleneck ===
<syntaxhighlight lang="bash">
# Test basic TCP connectivity (replace IP and port as needed)
nc -zv 192.168.1.10 3306


# Or using telnet
==== Identify CPU Bottleneck Using Manager Commands ====
telnet 192.168.1.10 3306
</syntaxhighlight>


If you see "Connection refused", the database service is not running or not listening on that port.
VoIPmonitor provides manager commands to monitor thread CPU usage in real-time. This is essential for identifying which thread is saturated.


;4. Test MySQL authentication using credentials from <code>voipmonitor.conf</code>:
'''Connect to manager interface:'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
mysql -h 192.168.1.10 -P 3306 -u root -p'your_password' voipmonitor
# Via Unix socket (local, recommended)
</syntaxhighlight>
echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket


Commands to run inside mysql client to verify:
# Via TCP port 5029 (remote or local)
<syntaxhighlight lang="sql">
echo 'sniffer_threads' | nc 127.0.0.1 5029
-- Check if connected correctly
SELECT USER(), CURRENT_USER();


-- Check database exists
# Monitor continuously (every 2 seconds)
SHOW DATABASES LIKE 'voipmonitor';
watch -n 2 "echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket"
 
-- Test write access
USE voipmonitor;
SHOW TABLES;
EXIT;
</syntaxhighlight>
</syntaxhighlight>


;5. Compare with a working sensor's configuration:
{{Note|1=TCP port 5029 is encrypted by default. For unencrypted access, set <code>manager_enable_unencrypted = yes</code> in voipmonitor.conf (security risk on public networks).}}
If you have other sensors that successfully connect to the database, compare their configuration files:
<syntaxhighlight lang="bash">
diff <(grep -E "^mysql" /etc/voipmonitor.conf) <(grep -E "^mysql" /path/to/working/sensor/voipmonitor.conf)
</syntaxhighlight>


;6. Check firewall and network connectivity:
'''Example output:'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="text">
# Test network reachability
t0 - binlog1 fifo pcap read          (  12345) :  78.5  FIFO  99    1234
ping -c 4 192.168.1.10
t2 - binlog1 pb write                (  12346) :  12.3              456
 
rtp thread binlog1 binlog1 0        (  12347) :  8.1               234
# Check if MySQL port is reachable
rtp thread binlog1 binlog1 1        ( 12348) :  6.2              198
nc -zv 192.168.1.10 3306
t1 - binlog1 call processing        (  12349) :  4.5              567
 
tar binlog1 compression 0            ( 12350) :  3.2                89
# Check firewall rules (if using firewalld)
firewall-cmd --list-ports
 
# Check firewall rules (if using iptables)
iptables -L -n | grep 3306
</syntaxhighlight>
</syntaxhighlight>


;7. Verify MySQL/MariaDB service is running:
'''Column interpretation:'''
On the database server, check if the service is active:
{| class="wikitable"
<syntaxhighlight lang="bash">
|-
# Check MySQL/MariaDB service status
! Column !! Description
systemctl status mariadb    # or systemctl status mysql
|-
| Thread name || Descriptive name (t0=capture, t1=call processing, t2=packet buffer write)
|-
| (TID) || Linux thread ID (useful for <code>top -H -p TID</code>)
|-
| CPU % || Current CPU usage percentage - '''key metric'''
|-
| Sched || Scheduler type (FIFO = real-time, empty = normal)
|-
| Priority || Thread priority
|-
| CS/s || Context switches per second
|}


# Restart service if needed
'''Critical threads to watch:'''
systemctl restart mariadb
{| class="wikitable"
|-
! Thread !! Role !! If at 90-100%
|-
| '''t0''' (pcap read) || Packet capture from NIC || '''Single-core limit reached!''' Cannot parallelize. Need DPDK/Napatech.
|-
| '''t2''' (pb write) || Packet buffer processing || Processing bottleneck. Check t2CPU breakdown.
|-
| '''rtp thread''' || RTP packet processing || Threads auto-scale. If still saturated, consider DPDK/Napatech.
|-
| '''tar compression''' || PCAP archiving || I/O bottleneck (compression waiting for disk)
|-
| '''mysql store''' || Database writes || Database bottleneck. Check SQLq metric.
|}


# Check which port MySQL is listening on
{{Warning|If '''t0 thread is at 90-100%''', you have hit the fundamental single-core capture limit. The t0 thread reads packets from the kernel and '''cannot be parallelized'''. Disabling features like jitterbuffer will NOT help - those run on different threads. The only solutions are:
ss -tulpn | grep mysql
* '''Reduce captured traffic''' using <code>interface_ip_filter</code> or BPF <code>filter</code>
</syntaxhighlight>
* '''Use kernel bypass''' ([[DPDK]] or [[Napatech]]) which eliminates kernel overhead entirely}}


;8. Apply configuration changes and restart the sensor:
==== Interpreting t2CPU Detailed Breakdown ====
<syntaxhighlight lang="bash">
# Restart the VoIPmonitor service to apply changes
systemctl restart voipmonitor


# Alternatively, reload without full restart (if supported in your version)
The syslog status line shows <code>t2CPU</code> with detailed sub-metrics:
echo 'reload' | nc 127.0.0.1 5029
<syntaxhighlight lang="text">
 
t2CPU[pb:10/ d:39/ s:24/ e:17/ c:6/ g:6/ r:7/ rm:24/ rh:16/ rd:19/]
# Verify the service started successfully
systemctl status voipmonitor
 
# Check logs for database connection confirmation
journalctl -u voipmonitor -n 20
</syntaxhighlight>
</syntaxhighlight>
=== Common Troubleshooting Scenarios ===


{| class="wikitable"
{| class="wikitable"
|-
|-
! Scenario !! Symptom !! Solution
! Code !! Function !! High Value Indicates
|-
|-
| Database server IP changed || "Can't connect to MySQL server on '10.1.1.10' (111)" || Update <code>mysqlhost</code> in <code>voipmonitor.conf</code>
| '''pb''' || Packet buffer output || Buffer management overhead
|-
|-
| Wrong credentials || "Access denied for user" || Verify and update <code>mysqlusername</code> and <code>mysqlpassword</code>
| '''d''' || Dispatch || Structure creation bottleneck
|-
|-
| Database service not running || "Connection refused (111)" || Start service: <code>systemctl start mariadb</code>
| '''s''' || SIP parsing || Complex/large SIP messages
|-
|-
| Firewall blocking port || <code>nc</code> shows "refused" but MySQL is running || Open port 3306 in firewall
| '''e''' || Entity lookup || Call table lookup overhead
|-
|-
| Localhost vs remote confusion || Works locally but fails from sensor || Use actual IP address instead of <code>localhost</code>
| '''c''' || Call processing || Call state machine processing
|-
| '''g''' || Register processing || High REGISTER volume
|-
| '''r, rm, rh, rd''' || RTP processing stages || High RTP volume (threads auto-scale)
|}
|}


For more detailed information about all <code>mysql*</code> configuration parameters, see [[Sniffer_configuration#Database_Configuration]].
'''Thread auto-scaling:''' VoIPmonitor automatically spawns additional threads when load increases:
* If '''d''' > 50% → SIP parsing thread ('''s''') starts
* If '''s''' > 50% → Entity lookup thread ('''e''') starts
* If '''e''' > 50% → Call/register/RTP threads start


== Check for Storage Hardware Errors (HEAP FULL / packetbuffer Issues) ==
==== Configuration for High Traffic (>10,000 calls/sec) ====
If the sensor is crashing with "HEAP FULL" errors or showing "packetbuffer: MEMORY IS FULL" messages, you must distinguish between '''actual storage hardware failures''' (requires disk replacement) and '''performance bottlenecks''' (requires tuning).


;1. Check kernel message buffer for storage errors:
<syntaxhighlight lang="ini">
<syntaxhighlight lang="bash">
# /etc/voipmonitor.conf
dmesg -T | grep -iE "ext4-fs error|i/o error|nvram warning|ata.*failed|sda.*error|disk failure|smart error" | tail -50
 
# Increase buffer to handle processing spikes (value in MB)
# 10000 = 10 GB - can go higher (20000, 30000+) if RAM allows
# Larger buffer absorbs I/O and CPU spikes without packet loss
max_buffer_mem = 10000
 
# Use IP filter instead of BPF (more efficient)
interface_ip_filter = 10.0.0.0/8
interface_ip_filter = 192.168.0.0/16
# Comment out any 'filter' parameter
</syntaxhighlight>
</syntaxhighlight>


Look for these hardware error indicators:
==== CPU Optimizations ====
* <code>ext4-fs error</code> - Filesystem corruption or disk failure
* <code>I/O error</code> or <code>BUG: soft lockup</code> - Disk read/write failures
* <code>NVRAM WARNING: nvram_check: failed</code> - RAID controller battery/capacitor issues
* <code>ata.*: FAILED</code> - Hard drive SMART failure
* <code>Buffer I/O error</code> - Disk unable to complete operations


'''If you see ANY of these errors:'''
<syntaxhighlight lang="ini">
* The storage subsystem is failing and likely needs hardware replacement
# /etc/voipmonitor.conf
* Do not attempt performance tuning - replace the failed disk/RAID first
* Check SMART status: <code>smartctl -a /dev/sda</code>
* Check RAID health: <code>cat /proc/mdstat</code> or RAID controller tools


;2. If dmesg is clean of errors → Performance Bottleneck:
# Reduce jitterbuffer calculations to save CPU (keeps MOS-F2 metric)
If the kernel logs show no storage errors, the issue is a performance bottleneck (disk too slow, network latency, etc.).
jitterbuffer_f1 = no
jitterbuffer_f2 = yes
jitterbuffer_adapt = no


'''Check disk I/O performance:'''
# If MOS metrics are not needed at all, disable everything:
<syntaxhighlight lang="bash">
# jitterbuffer_f1 = no
# Current I/O wait (should be < 10% normally)
# jitterbuffer_f2 = no
iostat -x 5
# jitterbuffer_adapt = no
</syntaxhighlight>
 
==== Kernel Bypass Solutions (Extreme Loads) ====


# Detailed disk stats
When t0 thread hits 100% on standard NIC, kernel bypass is the only solution:
dstat -d


# Real-time disk latency
{| class="wikitable"
ioping -c 10 .
|-
</syntaxhighlight>
! Solution !! Type !! CPU Reduction !! Use Case
|-
| '''[[DPDK]]''' || Open-source || ~70% || Multi-gigabit on commodity hardware
|-
| '''[[Napatech]]''' || Hardware SmartNIC || >97% (< 3% at 10Gbit) || Extreme performance requirements
|}
 
==== Verify Improvement ====


'''Check NFS latency (if using NFS storage):'''
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Test NFS read/write latency
# Monitor thread CPU after changes
time dd if=/dev/zero of=/var/spool/voipmonitor/testfile bs=1M count=100
watch -n 2 "echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket | head -10"
time cat /var/spool/voipmonitor/testfile > /dev/null
rm /var/spool/voipmonitor/testfile


# Check NFS mount options
# Or monitor syslog
mount | grep nfs
journalctl -u voipmonitor -f
# t0CPU should drop, heap values should stay < 20%
</syntaxhighlight>
</syntaxhighlight>


'''Common performance solutions:'''
{{Note|1=After changes, monitor syslog <code>heap[A&#124;B&#124;C]</code> values - should stay below 20% during peak traffic. See [[Syslog_Status_Line]] for detailed metric explanations.}}
* Use SSD/NVMe for VoIPmonitor spool directory
* Ensure proper NIC queue settings for high-throughput NFS
* Check network switch port configuration for NFS
* Review [[Scaling]] guide for detailed optimization


See also [[IO_Measurement]] for comprehensive disk benchmarking tools.
== Storage Hardware Failure ==


== Check for OOM (Out of Memory) Issues ==
'''Symptom''': Sensor shows disconnected (red X) with "DROPPED PACKETS" at low traffic volumes.
If VoIPmonitor suddenly stops processing CDRs and a service restart temporarily restores functionality, the system may be experiencing OOM (Out of Memory) killer events. The Linux OOM killer terminates processes when available RAM is exhausted, and MySQL (<code>mysqld</code>) is a common target due to its memory-intensive nature.


;1. Check for OOM killer events in kernel logs:
'''Diagnosis''':
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# For Debian/Ubuntu
# Check disk health
grep -i "out of memory\|killed process" /var/log/syslog | tail -20
smartctl -a /dev/sda
 
# Check RAID status (if applicable)
cat /proc/mdstat
mdadm --detail /dev/md0
</syntaxhighlight>


# For CentOS/RHEL/AlmaLinux
Look for reallocated sectors, pending sectors, or RAID degraded state. Replace failing disk.
grep -i "out of memory\|killed process" /var/log/messages | tail -20


# Also check dmesg:
== OOM (Out of Memory) ==
dmesg | grep -i "killed process" | tail -10
</syntaxhighlight>


Typical OOM killer messages look like:
=== Identify OOM Victim ===
<syntaxhighlight lang="text">
Out of memory: Kill process 1234 (mysqld) score 123 or sacrifice child
Killed process 1234 (mysqld) total-vm: 12345678kB, anon-rss: 1234567kB
</syntaxhighlight>


;2. Monitor current memory usage:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Check available memory (look for low 'available' or 'free' values)
# Check for OOM kills
free -h
dmesg | grep -i "out of memory\|oom\|killed process"
journalctl --since "1 hour ago" | grep -i oom
</syntaxhighlight>


# Check per-process memory usage (sorted by RSS)
=== MySQL Killed by OOM ===
ps aux --sort=-%mem | head -15


# Check MySQL memory usage in bytes
Reduce InnoDB buffer pool:
cat /proc/$(pgrep mysqld)/status | grep -E "VmSize|VmRSS"
<syntaxhighlight lang="ini">
# /etc/mysql/my.cnf
innodb_buffer_pool_size = 2G  # Reduce from default
</syntaxhighlight>
</syntaxhighlight>


'''Warning signs:'''
=== Voipmonitor Killed by OOM ===
* Available memory consistently below 500MB during operation
* MySQL consuming most of the available RAM
* Swap usage near 100% (if swap is enabled)
* Frequent process restarts without clear error messages


;3. First Fix: Check and correct innodb_buffer_pool_size:
Reduce buffer sizes in voipmonitor.conf:
Before upgrading hardware, verify that <code>innodb_buffer_pool_size</code> is not set too high. This is a common cause of OOM incidents.
<syntaxhighlight lang="ini">
max_buffer_mem = 2000  # Reduce from default
ringbuffer = 50        # Reduce from default
</syntaxhighlight>


'''Calculate the correct buffer pool size:'''
=== Runaway External Process ===
For a server running both VoIPmonitor and MySQL on the same host:
 
<syntaxhighlight lang="text">
<syntaxhighlight lang="bash">
Formula: innodb_buffer_pool_size = (Total RAM - VoIPmonitor memory - OS overhead) / 2
# Find memory-hungry processes
ps aux --sort=-%mem | head -20


Example for a 32GB server:
# Kill orphaned/runaway process
- Total RAM: 32GB
kill -9 <PID>
- VoIPmonitor process memory (check with ps aux): ~2GB
- OS + other services overhead: ~2GB
- Available for buffer pool: 28GB
- Recommended innodb_buffer_pool_size = 14G
</syntaxhighlight>
</syntaxhighlight>
For servers limited to '''16GB RAM''' or when experiencing repeated MySQL OOM kills:


'''Edit the MariaDB configuration file:'''
<syntaxhighlight lang="ini">
<syntaxhighlight lang="ini">
# Common locations: /etc/mysql/my.cnf, /etc/mysql/mariadb.conf.d/50-server.cnf
# /etc/my.cnf or /etc/mysql/mariadb.conf.d/50-server.cnf
[mysqld]
# On 16GB server: 6GB buffer pool + 6GB MySQL overhead = 12GB total
# Leaves 4GB for OS + GUI, preventing OOM
innodb_buffer_pool_size = 6G


innodb_buffer_pool_size = 14G  # Adjust based on your calculation
# Enable write buffering (may lose up to 1s of data on crash but reduces memory pressure)
innodb_flush_log_at_trx_commit = 2
</syntaxhighlight>
</syntaxhighlight>


'''Restart MariaDB to apply:'''
Restart MySQL after changes:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
systemctl restart mariadb  # or systemctl restart mysql
systemctl restart mysql
# or
systemctl restart mariadb
</syntaxhighlight>
</syntaxhighlight>
=== SQL Queue Growth from Non-Call Data ===


;4. Second Fix: Reduce VoIPmonitor buffer memory usage:
If <code>sip-register</code>, <code>sip-options</code>, or <code>sip-subscribe</code> are enabled, non-call SIP-messages (OPTIONS, REGISTER, SUBSCRIBE, NOTIFY) can accumulate in the database and cause the SQL queue to grow unbounded. This increases MySQL memory usage and leads to OOM kills of mysqld.
VoIPmonitor allocates significant memory for packet buffers. The total buffer memory is calculated based on:
 
{| class="wikitable"
|-
! Parameter !! Default !! Description
|-
| <code>ringbuffer</code> || 50MB || Ring buffer size per interface (recommended ≥500MB for >100 Mbit traffic)
|-
| <code>max_buffer_mem</code> || 2000MB || Maximum buffer memory limit
|}


'''Total formula:''' Approximate total = (ringbuffer × number of interfaces) + max_buffer_mem
{{Warning|1=Even with reduced <code>innodb_buffer_pool_size</code>, SQL queue will grow indefinitely without cleanup of non-call data.}}


'''To reduce VoIPmonitor memory usage:'''
'''Solution: Enable automatic cleanup of old non-call data'''
<syntaxhighlight lang="ini">
<syntaxhighlight lang="ini">
# Edit /etc/voipmonitor.conf
# /etc/voipmonitor.conf
 
# cleandatabase=2555 automatically deletes partitions older than 7 years
# Reduce ringbuffer for each interface (e.g., from 50 to 20)
# Covers: CDR, register_state, register_failed, and sip_msg (OPTIONS/SUBSCRIBE/NOTIFY)
ringbuffer = 20
cleandatabase = 2555
 
# Reduce maximum buffer memory (e.g., from 2000 to 1000)
max_buffer_mem = 1000
 
# Alternatively, reduce the number of sniffing interfaces if not all are needed
interface = eth0,eth1  # Instead of eth0,eth1,eth2,eth3
</syntaxhighlight>
</syntaxhighlight>


'''After making changes:'''
Restart the sniffer after changes:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
systemctl restart voipmonitor
systemctl restart voipmonitor
</syntaxhighlight>
</syntaxhighlight>


'''Important notes:'''
{{Note|See [[Data_Cleaning]] for detailed configuration options and other <code>cleandatabase_*</code> parameters.}}
* Reducing <code>ringbuffer</code> may increase packet loss during traffic spikes
== Service Startup Failures ==
* Reducing <code>max_buffer_mem</code> affects how many packets can be buffered before being written to disk
 
* Monitor packet loss statistics in the GUI after reducing buffers to ensure acceptable performance
=== Interface No Longer Exists ===


;5. Solution: Increase physical memory (if buffer tuning is insufficient):
After OS upgrade, interface names may change (eth0 → ensXXX):
If correcting both MySQL and VoIPmonitor buffer settings does not resolve the OOM issues, upgrade the server's physical RAM. After upgrading:
* Verify memory improvements with <code>free -h</code>
* Recalculate and adjust <code>innodb_buffer_pool_size</code>
* Re-tune <code>ringbuffer</code> and <code>max_buffer_mem</code>
* Monitor for several days to ensure OOM events stop


== Sensor Upgrade Fails with "Permission denied" from /tmp ==
<syntaxhighlight lang="bash">
If the sensor upgrade process fails with "Permission denied" errors when executing scripts from the <code>/tmp</code> directory, or the service fails to restart after upgrade, the <code>/tmp</code> partition may be mounted with the <code>noexec</code> flag.
# Find current interface names
ip a


The <code>noexec</code> mount option prevents execution of any script or binary from the <code>/tmp</code> directory for security reasons. However, the VoIPmonitor sensor upgrade process uses <code>/tmp</code> for temporary script execution.
# Update all config locations
grep -r "interface" /etc/voipmonitor.conf /etc/voipmonitor.conf.d/
 
# Also check GUI: Settings → Sensors → Configuration
</syntaxhighlight>
 
=== Missing Dependencies ===


;1. Check the mount options for /tmp:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
mount | grep /tmp
# Install common missing package
</syntaxhighlight>
apt install libpcap0.8  # Debian/Ubuntu
Look for the <code>noexec</code> flag in the mount options:
yum install libpcap    # RHEL/CentOS
<syntaxhighlight lang="text">
/dev/sda2 on /tmp type ext4 rw,relatime,noexec,nosuid,nodev
</syntaxhighlight>
</syntaxhighlight>


;2. Remount /tmp without noexec (temporary fix):
== Network Interface Issues ==
 
=== Promiscuous Mode ===
 
Required for SPAN port monitoring:
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
mount -o remount,exec /tmp
# Enable
ip link set eth0 promisc on


# Verify the change:
# Verify
mount | grep /tmp
ip link show eth0 | grep PROMISC
</syntaxhighlight>
</syntaxhighlight>
The output should no longer contain <code>noexec</code>.


;3. Make the change permanent (edit /etc/fstab):
{{Note|Promiscuous mode is NOT required for ERSPAN/GRE tunnels where traffic is addressed to the sensor.}}
 
=== Interface Drops ===
 
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
nano /etc/fstab
# Check for drops
ip -s link show eth0 | grep -i drop
 
# If drops present, increase ring buffer
ethtool -G eth0 rx 4096
</syntaxhighlight>
</syntaxhighlight>


Remove the <code>noexec</code> option from the /tmp line:
=== Bonded/EtherChannel Interfaces ===
<syntaxhighlight lang="text">
 
# Before:
'''Symptom''': False packet loss when monitoring bond0 or br0.
/dev/sda2  /tmp  ext4  rw,relatime,noexec,nosuid,nodev  0 0


# After (remove noexec):
'''Solution''': Monitor physical interfaces, not logical:
/dev/sda2  /tmp  ext4  rw,relatime,nosuid,nodev  0 0
<syntaxhighlight lang="ini">
# voipmonitor.conf - use physical interfaces
interface = eth0,eth1
</syntaxhighlight>
</syntaxhighlight>


If <code>/tmp</code> is a separate partition, remount for changes to take effect:
=== Network Offloading Issues ===
 
'''Symptom''': Kernel errors like <code>bad gso: type: 1, size: 1448</code>
 
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
mount -o remount /tmp
# Disable offloading on capture interface
ethtool -K eth0 gso off tso off gro off lro off
</syntaxhighlight>
</syntaxhighlight>


;4. Re-run the sensor upgrade:
== Packet Ordering Issues ==
After fixing the mount options, retry the sensor upgrade process.
 
If SIP messages appear out of sequence:


== "No space left on device" Despite Disks Having Free Space ==
'''First''': Rule out Wireshark display artifact - disable "Analyze TCP sequence numbers" in Wireshark. See [[FAQ]].
If system services (like php-fpm, voipmonitor, or commands like <code>screen</code>) fail with a "No space left on device" error even though <code>df -h</code> shows sufficient disk space, the issue is likely with '''temporary filesystems''' (<code>/tmp</code>, <code>/run</code>) filling up, not with main disk storage.


;1. Check usage of temporary filesystems:
'''If genuine reordering''': Usually caused by packet bursts in network infrastructure. Use tcpdump to verify packets arrive out of order at the interface. Work with network admin to implement QoS or traffic shaping. For persistent issues, consider dedicated capture card with hardware timestamping (see [[Napatech]]).
<syntaxhighlight lang="bash">
{{Note|For out-of-order packets in '''client/server mode''' (multiple sniffers), see [[Sniffer_distributed_architecture]] for <code>pcap_queue_dequeu_window_length</code> configuration.}}
# Check /tmp usage
df -h /tmp


# Check /run usage
=== Solutions for SPAN/Mirroring Reordering ===
df -h /run
</syntaxhighlight>


If <code>/tmp</code> or <code>/run</code> show 100% usage despite main filesystems having free space, these temporary filesystems need to be cleaned.
If packets arrive out of order at the SPAN/mirror port (e.g., 302 responses before INVITE causing "000 no response" errors):


;2. Check what is consuming space:
1. '''Configure switch to preserve packet order''': Many switches allow configuring SPAN/mirror ports to maintain packet ordering. Consult your switch documentation for packet ordering guarantees in mirroring configuration.
<syntaxhighlight lang="bash">
# Find large files in /tmp
du -sh /tmp/* 2>/dev/null | sort -hr | head -20


# Check journal disk usage
2. '''Replace SPAN with TAP or packet broker''': Unlike software-based SPAN mirroring, hardware TAPs and packet brokers guarantee packet order. Consider upgrading to a dedicated TAP or packet broker device for mission-critical monitoring.
journalctl --disk-usage
== Database Issues ==
</syntaxhighlight>


;3. Immediate cleanup of journal logs:
=== SQL Queue Overload ===
System journal logs stored in <code>/run/log/journal/</code> can fill up the <code>/run</code> filesystem.
<syntaxhighlight lang="bash">
# Limit journal to 100MB total size
sudo journalctl --vacuum-size=100M


# Or limit by time (keep only last 2 days)
'''Symptom''': Growing <code>SQLq</code> metric, potential coredumps.
sudo journalctl --vacuum-time=2d
</syntaxhighlight>


;4. Permanent solution - Configure journal rotation:
Edit <code>/etc/systemd/journald.conf</code>:
<syntaxhighlight lang="ini">
<syntaxhighlight lang="ini">
[Journal]
# voipmonitor.conf - increase threads
SystemMaxUse=100M
mysqlstore_concat_limit_cdr = 1000
MaxRetentionSec=1month
cdr_check_exists_callid = 0
</syntaxhighlight>
</syntaxhighlight>


Apply changes:
=== Error 1062 - Lookup Table Limit ===
<syntaxhighlight lang="bash">
sudo systemctl restart systemd-journald
</syntaxhighlight>


;5. Quick fix - System reboot:
'''Symptom''': <code>Duplicate entry '16777215' for key 'PRIMARY'</code>
The quickest way to free space in <code>/tmp</code> and <code>/run</code> is a system reboot, as these filesystems are cleared on each boot.


== Check VoIPmonitor Logs for General Errors ==
'''Quick fix''':
After addressing the specific issues above, check the system logs for other error messages from the sensor process that may reveal additional problems.
<syntaxhighlight lang="ini">
 
# voipmonitor.conf
<syntaxhighlight lang="bash">
cdr_reason_string_enable = no
# For Debian/Ubuntu
tail -f /var/log/syslog | grep voipmonitor
 
# For CentOS/RHEL/AlmaLinux
tail -f /var/log/messages | grep voipmonitor
</syntaxhighlight>
</syntaxhighlight>


'''Common errors to look for:'''
See [[Database_troubleshooting#Database_Error_1062_-_Lookup_Table_Auto-Increment_Limit|Database Troubleshooting]] for complete solution.
* <code>"pcap_open_live(eth0) error: eth0: No such device"</code> - Wrong interface name
* <code>"Permission denied"</code> - Sensor not running with sufficient privileges
* Messages about connection issues - See [[#Troubleshoot MySQL/MariaDB Database Connection Errors|database troubleshooting]]
* Messages about dropping packets - See [[Scaling]] guide


== Benign Database Errors When Features Are Disabled ==
== Bad Packet Errors ==
Some VoIPmonitor features may generate harmless database errors when those features are not enabled in your configuration. These errors are '''benign''' and can be safely ignored.


=== Common Benign Error: Missing Tables ===
'''Symptom''': <code>bad packet with ether_type 0xFFFF detected on interface</code>
If you see MySQL errors stating that a table does not exist (e.g., "Table 'voipmonitor.ss7' doesn't exist") even though the corresponding feature is disabled, this is expected behavior.


'''Common examples:'''
'''Diagnosis''':
* Errors about the <code>ss7</code> table when <code>ss7 = no</code> in <code>voipmonitor.conf</code>
<syntaxhighlight lang="bash">
* Errors about the <code>register_failed</code>, <code>register_state</code>, or <code>sip_msg</code> tables when those features are disabled
# Run diagnostic (let run 30-60 seconds, then kill)
voipmonitor --check_bad_ether_type=eth0


=== Solution: Ignore or Suppress in Monitoring ===
# Find and kill the diagnostic process
Since these errors indicate that a feature is simply not active, they do not impact system functionality:
ps ax | grep voipmonitor
kill -9 <PID>
</syntaxhighlight>


# '''Do not change the configuration''' to fix these errors
Causes: corrupted packets, driver issues, VLAN tagging problems. Check <code>ethtool -S eth0</code> for interface errors.
# '''Add monitoring exceptions''' to suppress warnings for table-not-found errors (MySQL error code 1146)
# Configure alerting systems to exclude these specific SQL errors from notifications


=== When to Take Action ===
== Useful Diagnostic Commands ==
You only need to take action if:
* You actually want to use the feature (enable the corresponding configuration option)
* Errors persist about tables for features that '''are''' explicitly enabled in <code>voipmonitor.conf</code>


== Appendix: tshark Display Filter Syntax for SIP ==
=== tshark Filters for SIP ===
When using <code>tshark</code> to analyze SIP traffic, it is important to use the correct Wireshark display filter syntax.


=== Basic SIP Filters ===
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Show all SIP INVITE messages
# All SIP INVITEs
tshark -r capture.pcap -Y "sip.Method == INVITE"
tshark -r capture.pcap -Y "sip.Method == INVITE"


# Show all SIP messages (any method)
# Find specific phone number
tshark -r capture.pcap -Y "sip"
tshark -r capture.pcap -Y 'sip contains "5551234567"'
 
# Get Call-IDs
tshark -r capture.pcap -Y "sip.Method == INVITE" -T fields -e sip.Call-ID


# Show SIP and RTP traffic
# SIP errors (4xx, 5xx)
tshark -r capture.pcap -Y "sip || rtp"
tshark -r capture.pcap -Y "sip.Status-Code >= 400"
</syntaxhighlight>
</syntaxhighlight>


=== Search for Specific Phone Number or Text ===
=== Interface Statistics ===
 
<syntaxhighlight lang="bash">
<syntaxhighlight lang="bash">
# Find calls containing a specific phone number (e.g., 5551234567)
# Detailed NIC stats
tshark -r capture.pcap -Y 'sip contains "5551234567"'
ethtool -S eth0


# Find INVITE messages for a specific number
# Watch packet rates
tshark -r capture.pcap -Y 'sip.Method == INVITE && sip contains "5551234567"'
watch -n 1 'cat /proc/net/dev | grep eth0'
</syntaxhighlight>
</syntaxhighlight>


=== Extract Call-ID from Matching Calls ===
== See Also ==
<syntaxhighlight lang="bash">
# Get Call-ID for calls matching a phone number
tshark -r capture.pcap -Y 'sip.Method == INVITE && sip contains "5551234567"' -T fields -e sip.Call-ID


# Get Call-ID along with From and To headers
* [[Sniffer_configuration]] - Configuration parameter reference
tshark -r capture.pcap -Y 'sip.Method == INVITE' -T fields -e sip.Call-ID -e sip.from.user -e sip.to.user
* [[Sniffer_distributed_architecture]] - Client/server deployment
</syntaxhighlight>
* [[Capture_rules]] - GUI-based recording rules
* [[Sniffing_modes]] - SPAN, ERSPAN, GRE, TZSP setup
* [[Scaling]] - Performance optimization
* [[Database_troubleshooting]] - Database issues
* [[FAQ]] - Common questions and Wireshark display issues


=== Filter by IP Address ===
<syntaxhighlight lang="bash">
# SIP traffic from a specific source IP
tshark -r capture.pcap -Y "sip && ip.src == 192.168.1.100"


# SIP traffic between two hosts
tshark -r capture.pcap -Y "sip && ip.addr == 192.168.1.100 && ip.addr == 10.0.0.50"
</syntaxhighlight>


=== Filter by SIP Response Code ===
<syntaxhighlight lang="bash">
# Show all 200 OK responses
tshark -r capture.pcap -Y "sip.Status-Code == 200"


# Show all 4xx and 5xx error responses
tshark -r capture.pcap -Y "sip.Status-Code >= 400"


# Show 486 Busy Here responses
tshark -r capture.pcap -Y "sip.Status-Code == 486"
</syntaxhighlight>


=== Important Syntax Notes ===
{| class="wikitable"
|-
! Syntax Element !! Correct Usage !! Notes
|-
| Field names || <code>sip.Method</code>, <code>sip.Call-ID</code> || Case-sensitive
|-
| String matching || <code>sip contains "text"</code> || Use <code>contains</code> keyword
|-
| String quotes || Double quotes <code>"..."</code> || Not single quotes
|-
| Boolean operators || <code>&&</code>, <code>||</code>, <code>!</code> || AND, OR, NOT
|}


For a complete reference, see the [https://www.wireshark.org/docs/dfref/s/sip.html Wireshark SIP Display Filter Reference].


== AI Summary for RAG ==
== AI Summary for RAG ==
'''Summary:''' Systematic troubleshooting guide for VoIPmonitor sensor issues. Part 1 covers "no calls being captured": service startup problems (binary renamed after crash, unresponsive after GUI update), network traffic verification using tshark, GUI sensor statistics (packet drops counter), promiscuous mode requirements (needed for SPAN/RSPAN but not for ERSPAN/GRE/TZSP), voipmonitor.conf configuration checks (interface, sipport, filter), GUI capture rules with Skip option, database connection errors (Error 111 after migration), HEAP FULL errors (hardware vs performance issues), OOM killer problems (innodb_buffer_pool_size and ringbuffer/max_buffer_mem tuning), upgrade failures due to /tmp noexec flag, and "no space left" errors caused by full /tmp or /run filesystems. Part 2 covers "missing or one-way audio": verifying savertp=yes, RTP traffic presence, NAT alias configuration (natalias with correct two-parameter syntax, try reversing IP order if needed), rtpip_find_endpoints, rtpfromsdp_onlysip, SDP vs actual RTP port mismatch analysis using tshark/tcpdump, external device (SBC/media server) port modification issues, and distributed architecture constraints (SIP and RTP must be captured by same sensor).


'''Keywords:''' troubleshooting, no calls, tshark, promiscuous mode, SPAN, ERSPAN, GRE, TZSP, voipmonitor.conf, interface, sipport, capture rules, Skip, packet drops, sensor statistics, Settings → Sensors, ringbuffer, max_buffer_mem, OOM killer, innodb_buffer_pool_size, HEAP FULL, Connection refused 111, noexec, /tmp, journal logs, no space left on device, missing audio, one-way audio, no audio, RTP correlation, natalias, rtpip_find_endpoints, rtpfromsdp_onlysip, savertp, SDP port mismatch, SBC, media server, distributed architecture
<!-- This section is for AI/RAG systems. Do not edit manually. -->
 
=== Summary ===
Comprehensive troubleshooting guide for VoIPmonitor sniffer/sensor problems. Covers: verifying traffic reaches interface (tcpdump/tshark), diagnosing no calls recorded (service, config, capture rules, SPAN), missing audio/RTP issues (one-way audio, NAT, natalias, rtp_check_both_sides_by_sdp), PACKETBUFFER FULL errors (I/O vs CPU bottleneck diagnosis using syslog metrics heap/t0CPU/SQLq and Linux tools iostat/iotop/ioping), manager commands for thread monitoring (sniffer_threads via socket or port 5029), t0 single-core capture limit and solutions (DPDK/Napatech kernel bypass), I/O solutions (NVMe/SSD, async writes, pcap_dump_writethreads), CPU solutions (max_buffer_mem 10GB+, jitterbuffer tuning), OOM issues (MySQL buffer pool, voipmonitor buffers), network interface problems (promiscuous mode, drops, offloading), packet ordering, database issues (SQL queue, Error 1062).
 
=== Keywords ===
troubleshooting, sniffer, sensor, no calls, missing audio, one-way audio, RTP, PACKETBUFFER FULL, memory is FULL, buffer saturation, I/O bottleneck, CPU bottleneck, heap, t0CPU, t1CPU, t2CPU, SQLq, comp, tacCPU, iostat, iotop, ioping, sniffer_threads, manager socket, port 5029, thread CPU, t0 thread, single-core limit, DPDK, Napatech, kernel bypass, NVMe, SSD, async write, pcap_dump_writethreads, tar_maxthreads, max_buffer_mem, jitterbuffer, interface_ip_filter, OOM, out of memory, innodb_buffer_pool_size, promiscuous mode, interface drops, ethtool, packet ordering, SPAN, mirror, SQL queue, Error 1062, natalias, NAT, id_sensor, snaplen, capture rules, tcpdump, tshark


'''Key Questions:'''
=== Key Questions ===
* Why is VoIPmonitor not recording any calls?
* Why are no calls being recorded in VoIPmonitor?
* How do I check if VoIP traffic is reaching my sensor?
* How to diagnose PACKETBUFFER FULL or memory is FULL error?
* How do I check for packet drops in the GUI sensor statistics?
* How to determine if bottleneck is I/O or CPU?
* What is the acceptable value for # packet drops in Settings → Sensors?
* What do heap values in syslog mean?
* How do I diagnose packet drops in VoIPmonitor?
* What does t0CPU percentage indicate?
* Do I need promiscuous mode for ERSPAN or GRE tunnels?
* How to use sniffer_threads manager command?
* How do I fix "Connection refused (111)" database errors?
* How to connect to manager socket or port 5029?
* VoIPmonitor crashes with HEAP FULL error, what should I check?
* What to do when t0 thread is at 100%?
* How do I fix OOM killer issues on VoIPmonitor server?
* How to fix one-way audio or missing RTP?
* Why does sensor upgrade fail with permission denied from /tmp?
* How to configure natalias for NAT?
* "No space left on device" but disk has free space, what to check?
* How to increase max_buffer_mem for high traffic?
* Why is audio missing or one-way in the GUI CDR view?
* How to disable jitterbuffer to save CPU?
* How do I configure natalias for NAT scenarios?
* What causes OOM kills of voipmonitor or MySQL?
* How do I diagnose SDP vs RTP port mismatches?
* How to check disk I/O performance with iostat?
* What should I do if external SBC is modifying RTP ports?
* How to enable promiscuous mode on interface?
* How to fix packet ordering issues with SPAN?
* What is Error 1062 duplicate entry?
* How to verify traffic reaches capture interface?

Latest revision as of 19:08, 22 January 2026

Sniffer Troubleshooting

This page covers common VoIPmonitor sniffer/sensor problems organized by symptom. For configuration reference, see Sniffer_configuration. For performance tuning, see Scaling.

Critical First Step: Is Traffic Reaching the Interface?

⚠️ Warning: Before any sensor tuning, verify packets are reaching the network interface. If packets aren't there, no amount of sensor configuration will help. 

# Check for SIP traffic on the capture interface
tcpdump -i eth0 -nn "host <PROBLEMATIC_IP> and port 5060" -c 10

# If no packets: Network/SPAN issue - contact network admin
# If packets visible: Proceed with sensor troubleshooting below

Quick Diagnostic Checklist

Check Command Expected Result
Service running systemctl status voipmonitor Active (running)
Traffic on interface tshark -i eth0 -c 5 -Y "sip" SIP packets displayed
Interface errors ip -s link show eth0 No RX errors/drops
Promiscuous mode ip link show eth0 PROMISC flag present
Logs grep voip No critical errors
GUI rules Settings → Capture Rules No unexpected "Skip" rules

No Calls Being Recorded

Service Not Running

# Check status
systemctl status voipmonitor

# View recent logs
journalctl -u voipmonitor --since "10 minutes ago"

# Start/restart
systemctl restart voipmonitor

Common startup failures:

  • Interface not found: Check interface in voipmonitor.conf matches ip a output
  • Port already in use: Another process using the management port
  • License issue: Check License for activation problems

Wrong Interface or Port Configuration

# Check current config
grep -E "^interface|^sipport" /etc/voipmonitor.conf

# Example correct config:
# interface = eth0
# sipport = 5060

💡 Tip:

GUI Capture Rules Blocking

Navigate to Settings → Capture Rules and check for rules with action "Skip" that may be blocking calls. Rules are processed in order - a Skip rule early in the list will block matching calls.

See Capture_rules for detailed configuration.

SPAN/Mirror Not Configured

If tcpdump shows no traffic:

  1. Verify switch SPAN/mirror port configuration
  2. Check that both directions (ingress + egress) are mirrored
  3. Confirm VLAN tagging is preserved if needed
  4. Test physical connectivity (cable, port status)

See Sniffing_modes for SPAN, RSPAN, and ERSPAN configuration.

Filter Parameter Too Restrictive

If filter is set in voipmonitor.conf, it may exclude traffic: 

# Check filter
grep "^filter" /etc/voipmonitor.conf

# Temporarily disable to test
# Comment out the filter line and restart


Missing id_sensor Parameter

Symptom: SIP packets visible in Capture/PCAP section but missing from CDR, SIP messages, and Call flow.

Cause: The id_sensor parameter is not configured or is missing. This parameter is required to associate captured packets with the CDR database.

Solution: 

# Check if id_sensor is set
grep "^id_sensor" /etc/voipmonitor.conf

# Add or correct the parameter
echo "id_sensor = 1" >> /etc/voipmonitor.conf

# Restart the service
systemctl restart voipmonitor

💡 Tip: Use a unique numeric identifier (1-65535) for each sensor. Essential for multi-sensor deployments. See id_sensor documentation.

Missing Audio / RTP Issues

One-Way Audio (Asymmetric Mirroring)

Symptom: SIP recorded but only one RTP direction captured.

Cause: SPAN port configured for only one direction.

Diagnosis: 

# Count RTP packets per direction
tshark -i eth0 -Y "rtp" -T fields -e ip.src -e ip.dst | sort | uniq -c

If one direction shows 0 or very few packets, configure the switch to mirror both ingress and egress traffic.

RTP Not Associated with Call

Symptom: Audio plays in sniffer but not in GUI, or RTP listed under wrong call.

Possible causes:

1. SIP and RTP on different interfaces/VLANs: 

# voipmonitor.conf - enable automatic RTP association
auto_enable_use_blocks = yes

2. NAT not configured: 

# voipmonitor.conf - for NAT scenarios
natalias = <public_ip> <private_ip>

# If not working, try reversed order:
natalias = <private_ip> <public_ip>

3. External device modifying media ports:

If SDP advertises one port but RTP arrives on different port (SBC/media server issue): 

# Compare SDP ports vs actual RTP
tshark -r call.pcap -Y "sip.Method == INVITE" -V | grep "m=audio"
tshark -r call.pcap -Y "rtp" -T fields -e udp.dstport | sort -u

If ports don't match, the external device must be configured to preserve SDP ports - VoIPmonitor cannot compensate.

RTP Incorrectly Associated with Wrong Call (PBX Port Reuse)

Symptom: RTP streams from one call appear associated with a different CDR when your PBX aggressively reuses the same IP:port across multiple calls.

Cause: When PBX reuses media ports, VoIPmonitor may incorrectly correlate RTP packets to the wrong call based on weaker correlation methods.

Solution: Enable rtp_check_both_sides_by_sdp to require verification of both source and destination IP:port against SDP: 

# voipmonitor.conf - require both source and destination to match SDP
rtp_check_both_sides_by_sdp = yes

# Alternative (strict) mode - allows initial unverified packets
rtp_check_both_sides_by_sdp = strict

⚠️ Warning: Enabling this may prevent RTP association for calls using NAT, as the source IP:port will not match the SDP. Use natalias mappings or the strict setting to mitigate this.

Snaplen Truncation

Symptom: Large SIP messages truncated, incomplete headers.

Solution: 

# voipmonitor.conf - increase packet capture size
snaplen = 8192

For Kamailio siptrace, also check trace_msg_fragment_size in Kamailio config. See snaplen documentation.

PACKETBUFFER Saturation

Symptom: Log shows PACKETBUFFER: memory is FULL, truncated RTP recordings.

⚠️ Warning: This alert refers to VoIPmonitor's internal packet buffer (max_buffer_mem), NOT system RAM. High system memory availability does not prevent this error. The root cause is always a downstream bottleneck (disk I/O or CPU) preventing packets from being processed fast enough.

Before testing solutions, gather diagnostic data:

  • Check sensor logs: /var/log/syslog (Debian/Ubuntu) or /var/log/messages (RHEL/CentOS)
  • Generate debug log via GUI: Tools → Generate debug log

Diagnose: I/O vs CPU Bottleneck

⚠️ Warning: Do not guess the bottleneck source. Use proper diagnostics first to identify whether the issue is disk I/O, CPU, or database-related. Disabling storage as a test is valid but should be used to confirm findings, not as the primary diagnostic method.

Step 1: Check IO[] Metrics (v2026.01.3+)

Starting with version 2026.01.3, VoIPmonitor includes built-in disk I/O monitoring that directly shows disk saturation status: 

[283.4/283.4Mb/s] IO[B1.1|L0.7|U45|C75|W125|R10|WI1.2k|RI0.5k]

Quick interpretation:

Metric Meaning Problem Indicator
C (Capacity) % of disk's sustainable throughput used C ≥ 80% = Warning, C ≥ 95% = Saturated
L (Latency) Current write latency in ms L ≥ 3× B (baseline) = Saturated
U (Utilization) % time disk is busy U > 90% = Disk at limit

If you see DISK_SAT or WARN after IO[]: 

IO[B1.1|L8.5|U98|C97|W890|R5|WI12.5k|RI0.1k] DISK_SAT

→ This confirms I/O bottleneck. Skip to I/O Bottleneck Solutions.

For older versions or additional confirmation, continue with the steps below.

ℹ️ Note: See Syslog Status Line - IO[] section for detailed field descriptions.

Step 2: Read the Full Syslog Status Line

VoIPmonitor outputs a status line every 10 seconds. This is your first diagnostic tool: 

# Monitor in real-time
journalctl -u voipmonitor -f
# or
tail -f /var/log/syslog | grep voipmonitor

Example status line: 

calls[424] PS[C:4 S:41 R:13540] SQLq[C:0 M:0] heap[45|30|20] comp[48] [25.6Mb/s] t0CPU[85%] t1CPU[12%] t2CPU[8%] tacCPU[8|8|7|7%] RSS/VSZ[365|1640]MB

Key metrics for bottleneck identification:

Metric What It Indicates I/O Bottleneck Sign CPU Bottleneck Sign
heap[A|B|C] Buffer fill % (primary / secondary / processing) High A with low t0CPU High A with high t0CPU
t0CPU[X%] Packet capture thread (single-core, cannot parallelize) Low (<50%) High (>80%)
comp[X] Active compression threads Very high (maxed out) Normal
SQLq[C:X M:Y] Pending SQL queries Growing = database bottleneck Stable
tacCPU[...] TAR compression threads All near 100% = compression bottleneck Normal

Interpretation flowchart:

Step 3: Linux I/O Diagnostics

Use these standard Linux tools to confirm I/O bottleneck:

Install required tools: 

# Debian/Ubuntu
apt install sysstat iotop ioping

# CentOS/RHEL
yum install sysstat iotop ioping

2a) iostat - Disk utilization and wait times 

# Run for 10 intervals of 2 seconds
iostat -xz 2 10

Key output columns: 

Device   r/s     w/s   rkB/s   wkB/s  await  %util
sda     12.50  245.30  50.00  1962.40  45.23  98.50
Column Description Problem Indicator
%util Device utilization percentage > 90% = disk saturated
await Average I/O wait time (ms) > 20ms for SSD, > 50ms for HDD = high latency
w/s Writes per second Compare with disk's rated IOPS

2b) iotop - Per-process I/O usage 

# Show I/O by process (run as root)
iotop -o

Look for voipmonitor or mysqld dominating I/O. If voipmonitor shows high DISK WRITE but system %util is 100%, disk cannot keep up.

2c) ioping - Quick latency check 

# Test latency on VoIPmonitor spool directory
cd /var/spool/voipmonitor
ioping -c 20 .

Expected results:

Storage Type Healthy Latency Problem Indicator
NVMe SSD < 0.5 ms > 2 ms
SATA SSD < 1 ms > 5 ms
HDD (7200 RPM) < 10 ms > 30 ms

Step 4: Linux CPU Diagnostics

3a) top - Overall CPU usage 

# Press '1' to show per-core CPU
top

Look for:

  • Individual CPU core at 100% (t0 thread is single-threaded)
  • High %wa (I/O wait) vs high %us/%sy (CPU-bound)

3b) Verify voipmonitor threads 

# Show voipmonitor threads with CPU usage
top -H -p $(pgrep voipmonitor)

If one thread shows ~100% CPU while others are low, you have a CPU bottleneck on the capture thread (t0).

Step 5: Decision Matrix

Observation Likely Cause Go To
heap high, t0CPU > 80%, iostat %util low CPU Bottleneck CPU Solution
heap high, t0CPU < 50%, iostat %util > 90% I/O Bottleneck I/O Solution
heap high, t0CPU < 50%, iostat %util < 50%, SQLq growing Database Bottleneck Database Solution
heap normal, comp maxed, tacCPU all ~100% Compression Bottleneck (type of I/O) I/O Solution

Step 6: Confirmation Test (Optional)

After identifying the likely cause with the tools above, you can confirm with a storage disable test: 

# /etc/voipmonitor.conf - temporarily disable all storage
savesip = no
savertp = no
savertcp = no
savegraph = no

systemctl restart voipmonitor
# Monitor for 5-10 minutes during peak traffic
journalctl -u voipmonitor -f | grep heap
  • If heap values drop to near zero → confirms I/O bottleneck
  • If heap values remain high → confirms CPU bottleneck

⚠️ Warning: Remember to re-enable storage after testing! This test causes call recordings to be lost.

Solution: I/O Bottleneck

ℹ️ Note: If you see IO[...] DISK_SAT or WARN in the syslog status line (v2026.01.3+), disk saturation is already confirmed. See IO[] Metrics for details.

Quick confirmation (for older versions):

Temporarily save only RTP headers to reduce disk write load: 

# /etc/voipmonitor.conf
savertp = header

Restart the sniffer and monitor. If heap usage stabilizes and "MEMORY IS FULL" errors stop, the issue is confirmed to be storage I/O.

Check storage health before upgrading: 

# Check drive health
smartctl -a /dev/sda

# Check for I/O errors in system logs
dmesg | grep -i "i/o error\|sd.*error\|ata.*error"

Look for reallocated sectors, pending sectors, or I/O errors. Replace failing drives before considering upgrades.

Storage controller cache settings:

Storage Type Recommended Cache Mode
HDD / NAS WriteBack (requires battery-backed cache)
SSD WriteThrough (or WriteBack with power loss protection)

Use vendor-specific tools to configure cache policy (megacli, ssacli, perccli).

Storage upgrades (in order of effectiveness):

Solution IOPS Improvement Notes
NVMe SSD 50-100x vs HDD Best option, handles 10,000+ concurrent calls
SATA SSD 20-50x vs HDD Good option, handles 5,000+ concurrent calls
RAID 10 with BBU 5-10x vs single disk Enable WriteBack cache (requires battery backup)
Separate storage server Variable Use client/server mode

Filesystem tuning (ext4): 

# Check current mount options
mount | grep voipmonitor

# Recommended mount options for /var/spool/voipmonitor
# Add to /etc/fstab: noatime,data=writeback,barrier=0
# WARNING: barrier=0 requires battery-backed RAID

Verify improvement: 

# After changes, monitor iostat
iostat -xz 2 10
# %util should drop below 70%, await should decrease

Solution: CPU Bottleneck

Identify CPU Bottleneck Using Manager Commands

VoIPmonitor provides manager commands to monitor thread CPU usage in real-time. This is essential for identifying which thread is saturated.

Connect to manager interface: 

# Via Unix socket (local, recommended)
echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket

# Via TCP port 5029 (remote or local)
echo 'sniffer_threads' | nc 127.0.0.1 5029

# Monitor continuously (every 2 seconds)
watch -n 2 "echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket"

ℹ️ Note: TCP port 5029 is encrypted by default. For unencrypted access, set manager_enable_unencrypted = yes in voipmonitor.conf (security risk on public networks).

Example output: 

t0 - binlog1 fifo pcap read          (  12345) :  78.5  FIFO  99     1234
t2 - binlog1 pb write                (  12346) :  12.3               456
rtp thread binlog1 binlog1 0         (  12347) :   8.1               234
rtp thread binlog1 binlog1 1         (  12348) :   6.2               198
t1 - binlog1 call processing         (  12349) :   4.5               567
tar binlog1 compression 0            (  12350) :   3.2                89

Column interpretation:

Column Description
Thread name Descriptive name (t0=capture, t1=call processing, t2=packet buffer write)
(TID) Linux thread ID (useful for top -H -p TID)
CPU % Current CPU usage percentage - key metric
Sched Scheduler type (FIFO = real-time, empty = normal)
Priority Thread priority
CS/s Context switches per second

Critical threads to watch:

Thread Role If at 90-100%
t0 (pcap read) Packet capture from NIC Single-core limit reached! Cannot parallelize. Need DPDK/Napatech.
t2 (pb write) Packet buffer processing Processing bottleneck. Check t2CPU breakdown.
rtp thread RTP packet processing Threads auto-scale. If still saturated, consider DPDK/Napatech.
tar compression PCAP archiving I/O bottleneck (compression waiting for disk)
mysql store Database writes Database bottleneck. Check SQLq metric.

⚠️ Warning: If t0 thread is at 90-100%, you have hit the fundamental single-core capture limit. The t0 thread reads packets from the kernel and cannot be parallelized. Disabling features like jitterbuffer will NOT help - those run on different threads. The only solutions are:

  • Reduce captured traffic using interface_ip_filter or BPF filter
  • Use kernel bypass (DPDK or Napatech) which eliminates kernel overhead entirely

Interpreting t2CPU Detailed Breakdown

The syslog status line shows t2CPU with detailed sub-metrics: 

t2CPU[pb:10/ d:39/ s:24/ e:17/ c:6/ g:6/ r:7/ rm:24/ rh:16/ rd:19/]
Code Function High Value Indicates
pb Packet buffer output Buffer management overhead
d Dispatch Structure creation bottleneck
s SIP parsing Complex/large SIP messages
e Entity lookup Call table lookup overhead
c Call processing Call state machine processing
g Register processing High REGISTER volume
r, rm, rh, rd RTP processing stages High RTP volume (threads auto-scale)

Thread auto-scaling: VoIPmonitor automatically spawns additional threads when load increases:

  • If d > 50% → SIP parsing thread (s) starts
  • If s > 50% → Entity lookup thread (e) starts
  • If e > 50% → Call/register/RTP threads start

Configuration for High Traffic (>10,000 calls/sec)

# /etc/voipmonitor.conf

# Increase buffer to handle processing spikes (value in MB)
# 10000 = 10 GB - can go higher (20000, 30000+) if RAM allows
# Larger buffer absorbs I/O and CPU spikes without packet loss
max_buffer_mem = 10000

# Use IP filter instead of BPF (more efficient)
interface_ip_filter = 10.0.0.0/8
interface_ip_filter = 192.168.0.0/16
# Comment out any 'filter' parameter

CPU Optimizations

# /etc/voipmonitor.conf

# Reduce jitterbuffer calculations to save CPU (keeps MOS-F2 metric)
jitterbuffer_f1 = no
jitterbuffer_f2 = yes
jitterbuffer_adapt = no

# If MOS metrics are not needed at all, disable everything:
# jitterbuffer_f1 = no
# jitterbuffer_f2 = no
# jitterbuffer_adapt = no

Kernel Bypass Solutions (Extreme Loads)

When t0 thread hits 100% on standard NIC, kernel bypass is the only solution:

Solution Type CPU Reduction Use Case
DPDK Open-source ~70% Multi-gigabit on commodity hardware
Napatech Hardware SmartNIC >97% (< 3% at 10Gbit) Extreme performance requirements

Verify Improvement

# Monitor thread CPU after changes
watch -n 2 "echo 'sniffer_threads' | nc -U /tmp/vm_manager_socket | head -10"

# Or monitor syslog
journalctl -u voipmonitor -f
# t0CPU should drop, heap values should stay < 20%

ℹ️ Note: After changes, monitor syslog heap[A|B|C] values - should stay below 20% during peak traffic. See Syslog_Status_Line for detailed metric explanations.

Storage Hardware Failure

Symptom: Sensor shows disconnected (red X) with "DROPPED PACKETS" at low traffic volumes.

Diagnosis: 

# Check disk health
smartctl -a /dev/sda

# Check RAID status (if applicable)
cat /proc/mdstat
mdadm --detail /dev/md0

Look for reallocated sectors, pending sectors, or RAID degraded state. Replace failing disk.

OOM (Out of Memory)

Identify OOM Victim

# Check for OOM kills
dmesg | grep -i "out of memory\|oom\|killed process"
journalctl --since "1 hour ago" | grep -i oom

MySQL Killed by OOM

Reduce InnoDB buffer pool: 

# /etc/mysql/my.cnf
innodb_buffer_pool_size = 2G  # Reduce from default

Voipmonitor Killed by OOM

Reduce buffer sizes in voipmonitor.conf: 

max_buffer_mem = 2000  # Reduce from default
ringbuffer = 50        # Reduce from default

Runaway External Process

# Find memory-hungry processes
ps aux --sort=-%mem | head -20

# Kill orphaned/runaway process
kill -9 <PID>

For servers limited to 16GB RAM or when experiencing repeated MySQL OOM kills: 

# /etc/my.cnf or /etc/mysql/mariadb.conf.d/50-server.cnf
[mysqld]
# On 16GB server: 6GB buffer pool + 6GB MySQL overhead = 12GB total
# Leaves 4GB for OS + GUI, preventing OOM
innodb_buffer_pool_size = 6G

# Enable write buffering (may lose up to 1s of data on crash but reduces memory pressure)
innodb_flush_log_at_trx_commit = 2

Restart MySQL after changes: 

systemctl restart mysql
# or
systemctl restart mariadb

SQL Queue Growth from Non-Call Data

If sip-register, sip-options, or sip-subscribe are enabled, non-call SIP-messages (OPTIONS, REGISTER, SUBSCRIBE, NOTIFY) can accumulate in the database and cause the SQL queue to grow unbounded. This increases MySQL memory usage and leads to OOM kills of mysqld.

⚠️ Warning: Even with reduced innodb_buffer_pool_size, SQL queue will grow indefinitely without cleanup of non-call data.

Solution: Enable automatic cleanup of old non-call data 

# /etc/voipmonitor.conf
# cleandatabase=2555 automatically deletes partitions older than 7 years
# Covers: CDR, register_state, register_failed, and sip_msg (OPTIONS/SUBSCRIBE/NOTIFY)
cleandatabase = 2555

Restart the sniffer after changes: 

systemctl restart voipmonitor

ℹ️ Note: See Data_Cleaning for detailed configuration options and other cleandatabase_* parameters.

Service Startup Failures

Interface No Longer Exists

After OS upgrade, interface names may change (eth0 → ensXXX): 

# Find current interface names
ip a

# Update all config locations
grep -r "interface" /etc/voipmonitor.conf /etc/voipmonitor.conf.d/

# Also check GUI: Settings → Sensors → Configuration

Missing Dependencies

# Install common missing package
apt install libpcap0.8  # Debian/Ubuntu
yum install libpcap     # RHEL/CentOS

Network Interface Issues

Promiscuous Mode

Required for SPAN port monitoring: 

# Enable
ip link set eth0 promisc on

# Verify
ip link show eth0 | grep PROMISC

ℹ️ Note: Promiscuous mode is NOT required for ERSPAN/GRE tunnels where traffic is addressed to the sensor.

Interface Drops

# Check for drops
ip -s link show eth0 | grep -i drop

# If drops present, increase ring buffer
ethtool -G eth0 rx 4096

Bonded/EtherChannel Interfaces

Symptom: False packet loss when monitoring bond0 or br0.

Solution: Monitor physical interfaces, not logical: 

# voipmonitor.conf - use physical interfaces
interface = eth0,eth1

Network Offloading Issues

Symptom: Kernel errors like bad gso: type: 1, size: 1448 

# Disable offloading on capture interface
ethtool -K eth0 gso off tso off gro off lro off

Packet Ordering Issues

If SIP messages appear out of sequence:

First: Rule out Wireshark display artifact - disable "Analyze TCP sequence numbers" in Wireshark. See FAQ.

If genuine reordering: Usually caused by packet bursts in network infrastructure. Use tcpdump to verify packets arrive out of order at the interface. Work with network admin to implement QoS or traffic shaping. For persistent issues, consider dedicated capture card with hardware timestamping (see Napatech).

ℹ️ Note: For out-of-order packets in client/server mode (multiple sniffers), see Sniffer_distributed_architecture for pcap_queue_dequeu_window_length configuration.

Solutions for SPAN/Mirroring Reordering

If packets arrive out of order at the SPAN/mirror port (e.g., 302 responses before INVITE causing "000 no response" errors):

1. Configure switch to preserve packet order: Many switches allow configuring SPAN/mirror ports to maintain packet ordering. Consult your switch documentation for packet ordering guarantees in mirroring configuration.

2. Replace SPAN with TAP or packet broker: Unlike software-based SPAN mirroring, hardware TAPs and packet brokers guarantee packet order. Consider upgrading to a dedicated TAP or packet broker device for mission-critical monitoring.

Database Issues

SQL Queue Overload

Symptom: Growing SQLq metric, potential coredumps. 

# voipmonitor.conf - increase threads
mysqlstore_concat_limit_cdr = 1000
cdr_check_exists_callid = 0

Error 1062 - Lookup Table Limit

Symptom: Duplicate entry '16777215' for key 'PRIMARY'

Quick fix: 

# voipmonitor.conf
cdr_reason_string_enable = no

See Database Troubleshooting for complete solution.

Bad Packet Errors

Symptom: bad packet with ether_type 0xFFFF detected on interface

Diagnosis: 

# Run diagnostic (let run 30-60 seconds, then kill)
voipmonitor --check_bad_ether_type=eth0

# Find and kill the diagnostic process
ps ax | grep voipmonitor
kill -9 <PID>

Causes: corrupted packets, driver issues, VLAN tagging problems. Check ethtool -S eth0 for interface errors.

Useful Diagnostic Commands

tshark Filters for SIP

# All SIP INVITEs
tshark -r capture.pcap -Y "sip.Method == INVITE"

# Find specific phone number
tshark -r capture.pcap -Y 'sip contains "5551234567"'

# Get Call-IDs
tshark -r capture.pcap -Y "sip.Method == INVITE" -T fields -e sip.Call-ID

# SIP errors (4xx, 5xx)
tshark -r capture.pcap -Y "sip.Status-Code >= 400"

Interface Statistics

# Detailed NIC stats
ethtool -S eth0

# Watch packet rates
watch -n 1 'cat /proc/net/dev | grep eth0'

See Also





AI Summary for RAG

Summary

Comprehensive troubleshooting guide for VoIPmonitor sniffer/sensor problems. Covers: verifying traffic reaches interface (tcpdump/tshark), diagnosing no calls recorded (service, config, capture rules, SPAN), missing audio/RTP issues (one-way audio, NAT, natalias, rtp_check_both_sides_by_sdp), PACKETBUFFER FULL errors (I/O vs CPU bottleneck diagnosis using syslog metrics heap/t0CPU/SQLq and Linux tools iostat/iotop/ioping), manager commands for thread monitoring (sniffer_threads via socket or port 5029), t0 single-core capture limit and solutions (DPDK/Napatech kernel bypass), I/O solutions (NVMe/SSD, async writes, pcap_dump_writethreads), CPU solutions (max_buffer_mem 10GB+, jitterbuffer tuning), OOM issues (MySQL buffer pool, voipmonitor buffers), network interface problems (promiscuous mode, drops, offloading), packet ordering, database issues (SQL queue, Error 1062).

Keywords

troubleshooting, sniffer, sensor, no calls, missing audio, one-way audio, RTP, PACKETBUFFER FULL, memory is FULL, buffer saturation, I/O bottleneck, CPU bottleneck, heap, t0CPU, t1CPU, t2CPU, SQLq, comp, tacCPU, iostat, iotop, ioping, sniffer_threads, manager socket, port 5029, thread CPU, t0 thread, single-core limit, DPDK, Napatech, kernel bypass, NVMe, SSD, async write, pcap_dump_writethreads, tar_maxthreads, max_buffer_mem, jitterbuffer, interface_ip_filter, OOM, out of memory, innodb_buffer_pool_size, promiscuous mode, interface drops, ethtool, packet ordering, SPAN, mirror, SQL queue, Error 1062, natalias, NAT, id_sensor, snaplen, capture rules, tcpdump, tshark

Key Questions

  • Why are no calls being recorded in VoIPmonitor?
  • How to diagnose PACKETBUFFER FULL or memory is FULL error?
  • How to determine if bottleneck is I/O or CPU?
  • What do heap values in syslog mean?
  • What does t0CPU percentage indicate?
  • How to use sniffer_threads manager command?
  • How to connect to manager socket or port 5029?
  • What to do when t0 thread is at 100%?
  • How to fix one-way audio or missing RTP?
  • How to configure natalias for NAT?
  • How to increase max_buffer_mem for high traffic?
  • How to disable jitterbuffer to save CPU?
  • What causes OOM kills of voipmonitor or MySQL?
  • How to check disk I/O performance with iostat?
  • How to enable promiscuous mode on interface?
  • How to fix packet ordering issues with SPAN?
  • What is Error 1062 duplicate entry?
  • How to verify traffic reaches capture interface?
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