Skip to content

Network Troubleshooting

This runbook helps diagnose common network issues in the homelab.

Typical problem areas:

  • DNS resolution
  • Reverse proxy routing
  • Cloudflare Tunnel connectivity
  • Internal service reachability

Quick Diagnostic Flow

  1. Check if the service is reachable internally
  2. Check DNS resolution
  3. Check reverse proxy routing
  4. Check container status
  5. Check Cloudflare tunnel connectivity

Test DNS Resolution

Check if internal DNS resolves correctly:

nslookup paperless.home
nslookup ha.home
nslookup rezepte.home

Or:

dig paperless.home

Expected result: IP of the Nginx Proxy Manager host.

Test Service Connectivity

Check if the service is reachable directly via IP.

Example:

curl http://192.168.0.51:8000
curl http://192.168.0.47:8080
curl http://192.168.0.46:8123

If this fails → the service itself is down.

Test Reverse Proxy

Test Nginx Proxy Manager routing:

curl -I http://homepage.home
curl -I http://paperless.home
curl -I http://rezepte.home

If DNS works but proxy fails → check Nginx configuration.

Check Docker Containers

Login to the Docker host:

pct enter 101

List containers:

docker ps

Check logs:

docker logs <container>

Check LXC Containers

List containers:

pct list

Enter container:

pct enter <id>

Verify services:

systemctl status <service>

Check Cloudflare Tunnel

Enter tunnel container:

pct enter 105

Check status:

systemctl status cloudflared

View logs:

journalctl -u cloudflared -f

Check AdGuard DNS

Open:

http://adguard.home

Look at:

Query Log

Verify that requests resolve correctly.

Common Problems

DNS resolves wrong IP

Cause:

  • incorrect AdGuard rewrite rule

Fix:

  • check AdGuard DNS rewrite settings

Reverse proxy returns 502

Cause:

  • backend container stopped
  • wrong port in proxy config

Fix:

  • verify service port
  • restart container

External domain not working

Cause:

  • Cloudflare tunnel not connected

Fix:

systemctl restart cloudflared

Useful Commands

docker ps
pct list
ss -tulpn
curl -I http://service.home
nslookup service.home

Notes

Most connectivity issues are caused by:

  • stopped containers
  • incorrect DNS rewrites
  • proxy configuration errors