VALVE ANTI CHEAT [info-thread]

Light Reading [about VAC]:
History

VAC was first released with Counter-Strike 1.4 in 2002, following Valve's decision to forego PunkBuster in preference of a proprietary system. The initial version, VAC1, saw success for a period, but in March or April 2004 updates ran dry as the Valve engineers maintaining it moved on to the production of its successor, VAC2.

Valve does not normally discuss VAC, and very little is known about its internal workings. However, on November 17, 2006 they announced that "new [VAC] technology" had caught "over 10,000" cheating attempts in the preceding week alone, the first real indication of the scale of anti-cheat operations. Not all of the accounts banned would have contained legitimate, purchased games, and there is no external audit on the figure.

As of 2010, unofficial sources estimate that over a million Steam accounts have been banned by VAC.

'Disadvantages'

1. A material hack, a (type of content hack) is undetectable by VAC2.
2. VAC cannot detect 'content hacks', where, for example, texture transparency and color are manipulated, since they do not involve modification of any program code. In the Source the option to create "pure" servers (sv_pure) that prevent custom content from overwriting the game's defaults was created to alleviate this.
3. Delayed bans, criticism & rationale
4. If a cheat is found the player's Steam account will be flagged as cheating immediately, but the player will not receive any indication of the detection. It is only after a delay of "days or even weeks" that the account is permanently banned from "VAC Secure" servers for that game, along with other games that use the same engine. (e.g. Valve's Source games, GoldSrc games, Unreal engine games). Valve never discloses which cheat was detected.

How do I tell if I am banned (or someone else)

VACBanned.com

Type in someones ID which is found in the URL bar at the top of the steam application (or in your normal URL box if you access steam online). It may take a few days for the ban to take effect as Valve don't want you knowing when the hack is detected so that they can catch more people while everyone thinks its still 'undetected'. If you use a variety of hacks too, VAC wont tell you which one got you caught.

All in all, a little annoying bit of red text will appear to all under your picture on the right of your profile. It won't tell anyone else what game you got banned for. Just that you have it on your 'record'.

You wont be able to play the game which you got banned for (multiplayer) through steam again. No exceptions.

But I like that game! How do I play it again!?

That game is not playable via steam. Try using a virtual lan network between buddies using Hamachi: ((Download). Alternatively, you can torrent it and look for other ways to play online with other people using Garena: (Download). At some point in the future I might make a tutorial on how to use these programs if enough people ask.

Is there a fine? Will I get taken to court?
No. Under TOS of steam, hackers are banned from using the software. They can't take you to court or issue fines since all you are doing is breaking steam's rules; not the law.

Is it like a server ban?
No. You won't be able to join any servers. And no 'admin' will unban you or give you warnings before being banned.
This is taken from steams website:
The best indicator that your account has been banned by VAC is if you receive this message when attempting to access a VAC-secure server:
If you receive an error message stating "STEAMID IS BANNED" (or other similar messages) when attempting to connect to a server, your account is not banned by VAC - server administrators may ban you from a particular server (we cannot prevent this - whoever runs the server can ban players for any reason they desire). If you find that you are banned from a large number of servers but your VAC status is in good standing, you have likely been banned by a third-party ban tool, such as Steambans or Punkbuster.

So if I have an undetected cheat, I'm clean?
No. This is taken from steams website:
How do I tell what games have VAC enabled?
Here is a list: VAC Game List

What should I do to make sure I don't get banned by VAC?
Steam has a set of reccomendations [which are found here] you should take to avoid being banned (by accident). The easiest way to avoid a ban is to ensure that the cheat is 100% safe and undetected!

Are there any other places I can check for more information?
Check the forums here. People there will answer your questions regarding steam or VAC. Don't mention MPGH though; its likely you will get flamed.
You could also ask here if you like, but I think I have covered just about everything. If there is something I have missed, tell me!