RBL's
These are online databases which contain sites that are known to send spam, or are known as open relay sites. DSMTP can check incoming connections against the list of servers on these databases in order to see whether they are listed, and then take various actions such as disposing of the message or rejecting it. This allows you to cut down on a lot of SPAM, and you don't have to be the one who has to update the list of "bad" servers each day :) as it's all automatic.
Occasionally there will be circumstances in which some servers will be in these databases, but you still wish to allow messages through from them, so we have also recently added exemption rules in order to allow for this. Please also note that in order to take advantage of these checks, DSMTP has to check each incoming connection, so this could cause time delays on some servers
ORBS was closed down a long time ago, and MAPS RBL has now moved to a subscription based service.
We have recently added generic functionality so that you can point DSMTP at any RBL server. You need to be running at least version 3 to use this.
Please let us know if you know any good RBL sites that are free and we will add them to our list.
rbl_vanish <host>
This causes DSMTP to accept all mail from the listed server as if everything
is normal, but then silently delete every message it has recieved.
rbl_ban <host>
This causes DSMTP to give 500 errors to each recipient given by the listed
server.
rbl_reject <host>
This causes DSMTP to give 500 errors to each recipient given by the listed
server.
MAPS RBL - (Please note that as of 31 July 2001 Maps RBL is now subscription based)
The settings are as follows (added in version 2.8e)
maps_action <ban | vanish | reject >
ban: This causes DSMTP to drop the incoming connection from the banned server after giving them a message that they have "no permission to talk".
reject: This causes DSMTP to give 500 errors to each recipient given by the listed server.
vanish: This causes DSMTP to accept all mail from the listed server as if everything is normal, but then silently delete every message it has recieved.
The exemption rules are as follows(added in 2.9a):
maps_exception <ip> can take a wildcard
maps_envelope
<string> If the string is contained in the rcpt to or mail from header
then they are exempted
maps_rcpt
<string> : If the rcpt to of the message header matches the string then
it is exempted
maps_mail
<string> : If the mail from of the message header matches the string
then it is exempted