[clug] E-mail spam problem

[Brendan Jurd]

2009/7/5 peter anderson <peterjohnanderson at gmail.com>:
> I
> am baffled at how this is done and was wondering if somebody on this
> list could explain how the spammers do this.

There's really nothing to it.  An email message is just a bunch of
text in a special format [1] fired at a mail server.  You can set the
"From:" header to whatever you like.  You can set any of the headers
to whatever you like.

If I wanted to I could send email to you that is "From" any address,
whether it has anything to do with me or not.  Spammers obviously
don't want you to know who they really are, so they falsify this
header.

Using the target address as the value for "From" is a neat trick
because some mail servers will check that the "From" address is valid.
 And since most people aren't going to blacklist their own address,
it's got a pretty good chance of getting through.

Cheers,
BJ

[1] http://www.faqs.org/rfcs/rfc822.html