This plugin patches the MTU warning you get when a query packet is longer than 1200 by changing it to 65000 which allows A2S queries to work (with all cvars).
Optional Extensions:
https://forums.alliedmods.net/showthread.php?t=229556
SteamWorks include required for compiling
If steamworks is installed the plugin will uses SteamWorks_SetRule to add rules (to bypass the kv file they added) If it is not installed it will try to patch out even more code by patching out the kv check. Using SteamWorks allows for the use of only 1 hack instead of 3.
Note: I dont know if this breaks anything. As far as I can tell it works fine.
Updated gamedata
here
Credits:
KyleS - for co-writing the plugin with me and testing.
asherkin - for bits of info along with his original RulesFix plugin.