Author: Peter Bowyer Date: To: exim-users Subject: Re: [Exim] spam calls home
Walt Reed wrote: > On Wed, Nov 26, 2003 at 05:10:02PM -0500, Richard Welty said:
>> On Wed, 26 Nov 2003 12:21:54 -0500 Ken Lowther
>> <hermit@???> wrote:
>>
>>> Many spams now call home by requesting a 'zero byte' gif when you
>>> open the page. This is also used for other people wanting to see if
>>> you opened the mail. Are there any rules for checking this?
>>
>> this is an MUA issue, not an MTA issue, making it offtopic here.
>
> Yeah, it's a little off topic, but it can by handled by preprocessing
> before mail gets to a MUA as well.
>
> Check out John Hardin's procmail security (google for it) which has
> some filtering for this kind of thing.
SpamAssassin has a test called HTML_WEB_BUGS which detects these things....
