I am setting up a Gitlab server (https://about.gitlab.com/) inside a virtual machine using KVM on a Ubuntu 14.04 host. My university charges us for every external IP address, so I cannot use bridged networking and have each virtual machine talk to the outside world directly. Instead, I have to use NAT and the host machine has to handle all the inbound traffic.
For HTTP, this is no big problem. I set up a reverse proxy using Nginx and dnsmaq to direct traffic based on the subdomain (e.g. git.example.com will go to the Gitlab server). But the Gitlab server also needs inbound SSH connections for git to work. I got as far as to figure out that Nginx only seems to provide reverse proxying for HTTP/S connections and I can't use it for SSH. It is also important that the Gitlab server is available on port 22, because otherwise all users would have to be instructed to use a different port.
Does anybody know whether I can use Apache with mod_proxy for this or another solution? The ideal setup would direct SSH traffic based on the subdomain such that
ssh example.com goes to the host,
ssh git.example.com goes to the git server, etc.