Gamespy Sees server, then doesn't see it...on and off lan

[plantage]

My dedicated server is on a LAN, but a DMZ. At times, the server is seen in gamespy, but then there are times it disappears.

A person (not on the lan, on his own connection) saw the server, then lost the server while it was still up. The server continues to appear and disappear and I am concerned. Obviously, it is hard to play on a server and have doubts that people can even see it exists!

I created a server.cfg (which execs on statup) that has the seta sv_gamespy "1" code inside, and also the
seta sv_master1 "mohmaster.2015.com"
seta sv_master2 "master0.gamespy.com"
seta sv_master3 "master1.gamespy.com"
codes.
Do any of these need to be in the target line...

I can not figure out why the server appears and disappears from my gamespy and people outside the lan. Any suggestions. Thanks

[SNYPE]

Even though you on on a DMZ some ports may still be blocked. I would check to see what ports are open or if there is a way to forward ports in your DMZ (check with the mfr?).
Here are the ports that must be open according to GameSpy:

6667 (IRC)
3783 (Voice Chat Port)
27900 (Master Server UDP Heartbeat)
28900 (Master Server List Request)
29900 (GP Connection Manager)
29901 (GP Search Manager)
13139 (Custom UDP Pings)
6515 (Dplay UDP)
6500 (Query Port)

Also make sure the ports required by MOhaa are open:

TCP port 12203 (default ), 12204 - 12218
Master UDP port: 12300
Server UDP port 12203 (default), 12204 -12218