Is it possible to have 2 domain names pointed to two different VMs running under Ubuntu Server? My dilema is that I only have 1 public facing IP address.
Here is a graphic of what I am trying to achieve:
/---FQDN1--->VM1
External IP ----
\---FQDN2--->VM2
I realize that there may be some pitfalls with this, such as having applications bind to different ports to avoid conflicts.
After reading online this may be possible with iptables, bind, and/or squid proxy.
First of all it is impossible to forward ports at the IP or transport layer to different internal machines based on the domain which the client is accessing. Because of that, what you want to do has to be done at a higher level of the network stack. But you may already have read this, since you are asking about proxies.
Moving one layer up the network stack, you find a wide range of different protocols. Some are easy to proxy based on hostname, some are impossible. I only know four protocols, which can be proxied in this way. Ranging from easiest to hardest, they are:
A standard HTTP proxy can handle the HTTP protocol for you. It works with any client sending a host header. This header is optional in HTTP/1.0 and mandatory in HTTP/1.1. By now HTTP/1.1 is more than a decade old, and you can expect pretty much all clients to support it by now.
HTTPS is a bit more tricky. It will only work with clients supporting SNI. I think you'll find a majority supporting it, but you may find a significant minority of clients still not supporting SNI. You can forward all clients without SNI support to one particular server, such that at least one of the domains can work for clients without SNI.
My recommendation is to assign a public IPv6 address to each server. That way clients with IPv6 support don't get the drawbacks of proxying, and you can use the IPv6 connectivity from the proxy to the actual server. This also means that the proxy can actually use DNS lookups to find the address of the server, which may simplify things.
I have implemented such a proxy with http and https support, so I know it is doable. But I think for your setup an off-the-shelf proxy is likely a better choice. I think squid can do it. On the other hand, I don't think iptables and bind will help you much.
The easiest way is using a reverse proxy which proxies your requests to the VM's. (I just assume we're speaking HTTP here)
