Port forwarding

[slayer 57]

I am trying to set up a hl2dm server. Seems like everything is working but nobody can see the server in steams list to join.
My question is do I have to use port forwarding if I am not using a router.

[Drocona]

If you are directly connected to the internet it shows up even "out of the box". (unless you have firewalls or certain virus scanners that block it)

Sounds like you simply have a gateway/router which means you need portforwarding, for that please use the search.