Spam filter and open relays
The Spamers worst nightmare.
Spamer have a problem sending out millions of emails. Their
ISP usually does not allow to email unlimited emails though
their relay. Spamers have to find other ways to do it. What
they are looking for is an open relay. Mostly an ISP or
a company mail server that is not protected. Once found
they will not only used to it, but tell others about it.
But they are not the only ones looking for open relays.
Several organizations do the same but for a very different
reason. They know that the Spamers send out Spam through
these relays. They find the relay and compile a list. These
lists are made available to the public. Some of them are
free, others are commercially available.
Xwall uses the SLS, RBL. Spamlist
or whatever you may like to call them. You can add your
favorite lists or use the predefined ones. An important
feature of Xwall is the Exclude List. It allows you to exclude
your business relations from the Spam test in case they
are on a relay list.
While Xwall makes full use
from the Spam relays it also includes the tools to make
sure you do not end up on one of the lists. Xwall protects
it's own SMTP relay several different ways including IP
address restrictions and authentication local or NTLM.