Well I guess that this one is definitely elligible for the "qmail security
challenge".
http://web.infoave.net/~dsill/qmail-challenge.html
If you don't count that as a bug in qmail, then I don't know what is a
bug...
Patrick.
"Scott Gifford" <[EMAIL PROTECTED]> wrote in message
news:<[EMAIL PROTECTED]>...
> Matt Brown <[EMAIL PROTECTED]> writes:
>
> > This has been a feature of recent spam, which is probably why it's now
> > an issue. Several spam senders are now having sender addresses of
> > <spammer>@<spamdomain>, where <spamdomain> resolves via DNS to
> > '0.0.0.0'.
> >
> > Eventually qmail rejects the message because it recognises that it's
> > looped around too much, of course.
>
> Right, but it's a very effective (perhaps inadvertant) DOS tool. If
> you can generate a stream of 10 messages/sec of these, it's the
> equivalent of generating about 300 messages/sec --- a great way of
> turning a puny dial-up connection into a mail server crushing machine.
>
> We had a spammer sending a huge number of messages to users at this
> address (<sigh> their fake bounce addresses are now getting on each
> others' list...), which was causing our not-processed queues to hover
> around 100, which was causing regular messages to be processed very
> slowly.
>
> Since qmail works around this simple mail loop for other address
> referring to the local machine, it should do so for 0.0.0.0 as well.
>
> ------ScottG.
>
