Can connect to external IP from L4D2; not in CS:GO

[chinagreenelvis]

I run dedicated servers for both games from the same machine I play on. My router supports loopback, so I use a dynamic DNS service to set my IP in the startup options.

The problem is that I can use my own external IP (or the DNS address associated with it) to connect to the server in Left 4 Dead 2, but not in Counter-Strike: Global Offensive.

I've also noticed that when started, the server for L4D2 says "dedicated: yes" while the CS:GO server says "dedicated: no". I'm not sure if that has anything to do with it.

Anyone know what it is that the games handle differently that would account for this problem?

[chinagreenelvis]

Apparently the solution is setting +net_public_adr to the external IP (or the DNS address) in the startup options.