I can get into my Linux box at home from work using port 23, and forwarding
to port 22 internally, for ssh. Port 23 is about the only port open in my
employer's firewall.

If I setup a webserver on Linux, is there anyway to intercept incoming
traffic on port 23, and forward to either 22 or 80, based on the protocol?
I.e. forward ssh to 22, and HTTP to 80, internally?