Port forward to different IP based on destination address
Hello all you lovely people!
I'm trying to figure out if I can port forward to different servers based on the destination domain.
I have a domain with a wildcard cert and I'd like to be able to route all traffic headed towards "1.domain.com" to a server I'm calling "1". I'd still like traffic headed to domain.com to go to where it's currently going, we can call this server "0", and to be able to have a 2.domain.com or 3 or 4 in the future.
I thought that having a port forward rule with:
interface: WAN
Protocol: any
source: any destination: a url alias including 1.domain.com
redirect target ip: local ip
This won't work. At the level you are looking to route the packets, there is no concept of which domain the request was intended for. You need a service that knows how to look at that packet, and forward it appropriately.
What you need to look into is a Reverse Proxy such as haproxy, caddy, or nginx (no specific order). I use haproxy to do something similar, but only on my internal network (with wireguard to access those when I am elsewhere).
Which ever reverse proxy you pick will be responsible for looking at those packets coming into it, and can determine the intended domain to route them appropriately, either through SNI, or more likely by unrwrapping the TLS on the packet.
I'd be careful with doing this, as you are letting whatever outside traffic into your network, so it's up to you to assess the risk for your use case and make the appropriate mitigations.
It will accept all traffic sent to it via the ports it is listening on, just like any other service. It doesn't have to forward everything though, and what it does with that is up to it's configuration options and what you do with those.
Since you mentioned the wildcard cert, I assumed you were talking about services that speak http/s, and that they'd probably be on port 443. Those were a lot of assumptions by me.
If it's not an http/s type service, what kind of services are we talking about?