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Re: [MiNT] OT: The test is wrong

On Mon, 17 Jun 2002, Thomas Binder wrote:

> address were outside the casema network (both were @dsbl.org), so
> it's definitely acting as a relay. The source IP address should
> not cause such checks to be skipped.

Definitely not, since it's only the source IP address that counts! The
from-address can be anything, and in fact I don't know any ISP smtp server
that checks this. It's easy for a spammer to enter a From-address that
complies with the domain the smtp server is in. Forging the IP address is
a lot harder. From-addresses don't mean a thing, especially not in spam

> Well, you should re-think that. A mail server that accepts mail
> that is addressed to AND from addresses not beloning to its own
> network is by definition an open relay. No matter what source IP
> you use for the STMP connect.

As we speak, a spam attack on my own mailserver is in progress without any
success. Someone from Chello.nl has been trying to relay mails over
smtp.bassment.nu using the from-address of one of my customers for the
last 20 days.  Fortunately, the server plays by my rules and not yours or
he would have succeeded. :)


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