On 8/12/05, Carlos Zottmann <[EMAIL PROTECTED]> wrote:
> Does anyone know a way to block web bugs (0x0 gifs) with squid?

Interesting question.

Since the function of a web bug is fulfilled when the URL is retrieved
from the remote server, and since Squid can't see the GIF's dimensions
until after the object is received, I'd say it's technically impossible
to effectively block web bugs using Squid, short of composing a regular
expression to match all likely tracking bug URLs (watch out for false
positives).

You could certainly modify Squid (or any caching proxy) to detect when
a received image has dimensions below a certain minimum, and react by
forcing any _future_ requests for that object to be served from cache
regardless of the headers supplied by the server or a cookie or other
header requested by the client.  This wouldn't help the first time any
user triggers a web bug, but would effectively keep private any future
requests for that same exact URL.

Kevin Kadow

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