Hi!
If you are having problems with people not being able to ping or connect to your server (shows up N/A in PING in the server browser), even though you are sure your router and firewalls are setup properly, try this:
edit your Land of the Dead\System\Server.INI file
Find the line that says "ServerBehindNAT="
If it says "True" set it to "False", if it says "False" set it to "True".
Try your server again.
Turning this option off seems to have fixed my personal connection.