some kind of mod? o.O

[MoR7eM]

sup guys,

just joined a survival game on the parish (bridge), everything went fine.
but then some message said that if you type !9 or something it will spawn a portal. after another match, the message said !build. and with my curiosity i tried it immediatly. when i did that, a window popped up. with that window i could spawn fences, ammo stacks, machineguns, stairs and all that stuff! it was kinda cool i gotta admit, did anyone know how this was possible? and how to do it?
thanks!
-Mor7em

[MoR7eM]

please respond!! and that portal worked with the command !p and not !9, sorry for that.

[Ada Wong]

They are called perks some servers have them and you can do alot of neat things with it.

[Stark Raven]

These are probably Sourcemods, which are server-side mods beyond the normal scope of the game. They aren't as easy to install as normal .vpk-style addons.