[MUD-Dev] Gearing up against GEAR

Vincent Archer archer at frmug.org
Sun Jul 22 12:10:15 New Zealand Standard Time 2001


According to Dan MacDonald:

> Here's a link to Dr.Twisters Gear page. Apparently it works for
> other Games as well, essentially what it does is multiply the
> packets sent By the client up to 256 times, confusing the server.

That's a slight misunderstanding. It does not multiply packets, per
se (if it duplicated packets, nothing special would happen). As Ted
originally postulated, Gear mucks your internal windows timers,
fooling the client into thinking that a second has elapsed when a
fraction (or multiple) has in fact elapsed.

So the client think it's running at 15 FPS instead of 30, and speeds
up all animations and action timers by the same factor.

Now, you'd say, why would the server trust the client on such a
matter?  Well, given that combat actions have a timing that is
smaller than the tolerable ping over Internet, there's no way the AC
server can validate *all* actions from the client and acknowledge
them, like this:

[Client tells STRIKE] -> [Server reports STRIKE allowed again now]

I'm surprised accelerated movement from GEAR works, given that, for
AC the server *does* process movement and has to acknowledge it.

How does one fight GEAR? I see no solution except to report the
timer on the client in the packet protocol. This allows the server
to check for time drift. If time drifts constantly and at a fast
rate, the client is probably GEARed.

Turbine apparently has tried to put some consistency checks against
GEARed clients, but unfortunately, under real-world conditions, a
good number of normal users went flagged for GEAR usage where all
they suffered was some CISCO overload somewhere slowing down packets
because its internal buffers were filling. And the chief problem is
that, apparently the GEAR detection...

  ... is done client-side and reported to the server :(

(a good hex editor, and the client no longer detects anything
suspicious)

--
	Vincent Archer			Email:	archer at frmug.org

All men are mortal.  Socrates was mortal.  Therefore, all men are Socrates.
							(Woody Allen)
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