Troubleshooting:Service Troubleshooting

Service Troubleshooting

This guide covers troubleshooting for reverse proxy services.

Common Issues

Issue: 502 Bad Gateway

Causes: Service not running on Synology NAS Wrong port number Service not accessible via VPN

Solutions:

= Test from VPS to NAS =
ping 10.8.0.2
curl http://10.8.0.2:PORT_NUMBER

= Check if service is listening =
= (from Synology NAS or via SSH) =
netstat -tlnp | grep PORT_NUMBER

Issue: SSL Certificate Failed

Causes: DNS not pointing to VPS Port 80 blocked Rate limiting from Let's Encrypt

Solutions:

= Check DNS =
nslookup newservice.jb-vpn.uk

= Verify port 80 is open =
curl -I http://newservice.jb-vpn.uk

= Check firewall =
sudo iptables -L -n -v | grep 80

Issue: Service Not Loading

Causes: Wrong proxy_pass URL Missing headers Service requires specific path

Solutions: Check nginx error log: tail -f /var/log/nginx/error.log Verify service works directly: curl http://10.8.0.2:PORT Test with different proxy_pass formats

Issue: Connection Timeout

Causes: VPN tunnel down Service not accessible Firewall blocking

Solutions:

= Check VPN =
ip addr show tun0
ping 10.8.0.2

= Check routing =
ip route | grep 10.8.0.2

= Test connectivity =
curl -v http://10.8.0.2:PORT_NUMBER

Diagnostic Commands

= Check service status =
systemctl status nginx

= Test nginx configuration =
nginx -t

= View error logs =
tail -f /var/log/nginx/error.log

= View access logs =
tail -f /var/log/nginx/access.log

= Check SSL certificates =
certbot certificates

= Test service directly =
curl -I https://service.jb-vpn.uk

Related Documentation

[Adding Services](index.md) - Service configuration

• [System Overview](index.md) - System architecture