Cannot connect to my dedicated, steam-group L4D2 server
Here are the steps I did to make my L4D2 Source Dedicated server (srcds.exe) show up in Steam Group on my FIOS home internet (discover LAN games is turned off in client, so not a false positive):
On my server firewall I opened all UDP and TCP port access for the program "srcds.exe" for public private and domain, both inbound and outbound.
On my router I forwarded "any" inbound port to 27015 and 26901 on my server.
Tweaked my srcds.exe command line so that the server would show "secure" while checking status in game (CLI inside L4D2 type "status"). Also, I switched from world server (255) to Western US (1) in my server config. I don't know if either of these helped exactly (probably not), but thought I'd share in case it did.
The key here is I did not know that you can receive on any port on your WAN IP, but that can go to any OTHER port on your LAN IP. I always thought it was one to one and only ever attempted port forwarding the ports one to one. As soon as I opened the inbound on my WAN source ports to "any", BAM!, my server showed up in Steam Group Servers. I wouldn't have ever known the fact that ports aren't one to one unless I used a tool called "livetcpudpwatch" to monitor ports opening while running my server in DMZ (for testing).
Here is my tweaked command line. I had tried with and without +ip and +port, but without seemed to work "best" for me, ymmv:
`srcds.exe -console -game left4dead2 +exec server.cfg +map c1m1_hotel -secure`
I am not a router specialist, so don't complain if your network gets hacked with these settings. My server is dedicated, and has no access to my network outside of serving L4D2, even so I feel these settings are low security risk, because the server and router can only pass traffic on 2 ports, and the only program listening on those ports is srcds.exe. If someone more router savvy wants to confirm my thinking, feel free.