Hey everyone! I'm having a tough time getting my IPtables rules to work the way I need for my multiple Docker containers. I have NGINX running on ports 80 and 443 (mapped from host to Docker) on its own bridge network. There's another service on a different bridge that uses port 80 (mapped from 8081 to 80). I've set up NGINX to only accept traffic from Cloudflare, but now I realize that my other service needs to allow all sources on port 80. The problem I'm facing is that my current IPtables rules affect all containers with open ports 80 and 443, rather than targeting just the NGINX container or the other service. Is there a way to create specific IPtables rules that only apply to certain containers by using their Docker IPs? I've seen examples in the Docker documentation that didn't quite work for me. Ideally, I want to use commands like `--ctorigdst` and `--ctorigdstport` to define the container and its port. Any help would be appreciated!
2 Answers
You really shouldn't be manually messing with IPtables on a Docker host. The recommended approach is to use a dedicated HTTP proxy like Traefik, Caddy, or NGINX Proxy Manager. These tools are designed to handle routing and IP whitelisting. For instance, with Traefik, you can use the 'ipallowlist' feature to limit traffic for specific containers by their respective networks. It simplifies the whole process. Have you looked into switching to one of those proxies?
That’s the tricky part indeed! You can either work with Cloudflare’s IPs and risk failing to capture real client IPs, or do the opposite. If possible, leverage one of these proxy tools to handle the IP whitelisting elegantly while still allowing NPM to log the correct addresses for security.
It sounds like using NGINX as a reverse proxy might be a good fit. You could set it up to be the only entry point for traffic on ports 80 and 443, and then have it route requests to the correct services. This way, your other service can handle everything on port 80 without being blocked by IPtables rules that affect all containers. You can also adjust logging and security measures with real client IPs using the X-Forwarded-For header. Have you considered reconfiguring your Docker network like this?
Absolutely! You can configure access policies in NGINX to allow specific IPs. Just be mindful of ensuring real client IPs are preserved using the headers correctly.
That makes sense! I hadn’t thought about using NGINX as a reverse proxy for everything. If I do that, can I still manage IP restrictions effectively? I want to ensure that my access policies work for those real client IPs.
I’m using NGINX Proxy Manager for one of my services already, but I’m not sure if it’s correct to route all my web traffic through it since not all of it is from Cloudflare. I’d like to get both the real client IP for fail2ban and still limit NPM traffic to Cloudflare.