Nginx

Nginx Reverse Proxy Configuration

This guide covers Nginx configuration as a reverse proxy for the VoIPmonitor GUI, addressing common issues with large data transfers and long-running operations.

Common Problems

Problem	Symptom	Solution
Large data requests	Errors downloading reports/PCAPs	Increase buffer sizes
Long operations	504 Gateway Timeout	Increase timeout values
SSO redirect loops	Google/Microsoft Sign-In fails	Add X-Forwarded-Proto header
Backend down	502 Bad Gateway	Check Apache/PHP-FPM status

Recommended Configuration

Add this configuration to your Nginx location block:

location / {
    proxy_pass http://127.0.0.1:80;

    # Buffer settings for large reports/PCAP downloads
    proxy_buffer_size 128k;
    proxy_buffers 4 256k;
    proxy_busy_buffers_size 256k;

    # Timeout settings (1 hour for long-running operations)
    proxy_connect_timeout 3600s;
    proxy_send_timeout 3600s;
    proxy_read_timeout 3600s;
    send_timeout 3600s;

    # Required headers
    proxy_set_header Host $host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

    # CRITICAL for SSO (Google/Microsoft Sign-In)
    proxy_set_header X-Forwarded-Proto $scheme;
}

⚠️ Warning: The X-Forwarded-Proto header is required for SSO (Google/Microsoft Sign-In) when SSL is terminated at Nginx. Without it, you will experience redirect loops.

Apply Changes

# Test configuration syntax
sudo nginx -t

# Reload configuration
sudo systemctl reload nginx

Troubleshooting

504 Gateway Timeout

Increase all timeout values in the Nginx configuration. The default timeouts are too short for:

• Large CDR exports
• Bulk PCAP downloads
• Complex report generation

502 Bad Gateway

The backend service is not responding. Check:

# Check Apache status
systemctl status apache2

# Or check PHP-FPM status
systemctl status php-fpm

SSO Redirect Loops

If Google or Microsoft Sign-In fails with redirect loops:

1. Verify X-Forwarded-Proto header is set 2. Check that the header value matches the actual protocol (https) 3. Ensure the GUI's configured URL matches the public URL

Apache Alternative (Without Nginx)

If using Apache with mod_fcgid directly (not behind Nginx), increase these timeouts in Apache configuration:

FcgidIOTimeout 900
FcgidIdleTimeout 900
FcgidConnectTimeout 900
FcgidProcessLifeTime 900

# Apply changes
systemctl restart apache2   # Debian/Ubuntu
systemctl restart httpd     # RHEL/CentOS

💡 Tip: These settings fix "server side error - connection to the web server was lost" when loading dashboards or charts.

See Also

• GUI Installation
• Google Sign-In Configuration
• Microsoft Sign-In Configuration
• GUI Troubleshooting

AI Summary for RAG

Summary: Nginx reverse proxy configuration guide for VoIPmonitor GUI. Covers buffer settings (proxy_buffer_size, proxy_buffers) for large data downloads and timeout settings (proxy_read_timeout, etc.) set to 3600s to prevent 504 errors on long operations. Critical: X-Forwarded-Proto header must be set for SSO (Google/Microsoft Sign-In) to prevent redirect loops when SSL terminates at Nginx. Also covers Apache mod_fcgid timeout configuration (FcgidIOTimeout, FcgidIdleTimeout) for environments not using Nginx.

Keywords: nginx, reverse proxy, 504 gateway timeout, 502 bad gateway, proxy_buffer_size, proxy_buffers, proxy_read_timeout, X-Forwarded-Proto, SSO, SSL termination, redirect loop, apache, mod_fcgid, FcgidIOTimeout, timeout configuration

Key Questions:

• How do I fix 504 Gateway Timeout in Nginx with VoIPmonitor?
• What are the recommended Nginx buffer settings for VoIPmonitor?
• Why does Google/Microsoft Sign-In fail behind Nginx reverse proxy?
• How do I fix SSO redirect loops with SSL termination?
• What are the recommended timeout values for Nginx with VoIPmonitor?
• How do I fix Apache timeout errors when loading VoIPmonitor dashboards?