Simple question, difficult solution. I can’t work it out. I have a server at home with a site-to-site VPN to a server in the cloud. The server in the cloud has a public IP.
I want people to access server in the cloud and it should forward traffic through the VPN. I have tried this and it works. I’ve tried with nginx streams, frp and also HAProxy. They all work, but, in the server at home logs I can only see that people are connecting from the site-to-site VPN, not their actual source IP.
Is there any solution (program/Docker image) that will take a port, forward it to another host (or maybe another program listening on the host) that then modifies the traffic to contain the real source IP. The whole idea is that in the server logs I want to see people’s real IP addresses, not the server in the cloud private VPN IP.
The way I would solve this is by putting nginx or other reverse proxy directly on your instance in the cloud. You can use this to set one of the well known proxy headers and proxies as others have mentioned and have this then proxy to your backend instances over the VPN (even if it’s pointing to an internal nginx instance). Then the access logs on your cloud instance will also contain the actual IP address of the client, setting headers will obviously only work for HTTP traffic, there really isn’t a similar mechanism for TCP/UDP traffic as those are layer 3 and HTTP is layer 4. If you are concerned about it you can always ship the logs to somewhere on prem as well.
For TCP/UDP traffic, you’d just move the problem on another box. The application logs would report connections from 127.0.0.1 (the local proxy), and not the client IP.
Yep you are correct, that’s what I was trying to when I was talking about the logs on the public instance and forwarding them to a central place of that is important information, sorry if it didn’t make sense, I must have been tired haha.
I forgot before, it is also possible use ProxyProtocol for TCP applications but the application will need to understand it for it to show in the application logs. It would also be possible to use this to allow the on-prem instance (nginx->nginx let’s say) to see the true client IP from the public instance, the exact configuration is implementation dependent though.