RBL's - Revision history

Ledhed at 20:49, 25 March 2007

2007-03-25T20:49:17Z

Ledhed at 20:44, 25 March 2007

2007-03-25T20:44:48Z

Ledhed at 20:36, 25 March 2007

2007-03-25T20:36:28Z

Ledhed at 20:35, 25 March 2007

2007-03-25T20:35:30Z

New page

'''Real Time Blacklists'''
RBL's are lists of IP addresses which are known to send SPAM.

'''Reference:'''
http://www.spamhaus.org

== How RBL's Work ==
RBL's work through DNS queries.
Mail servers perform a dns lookup of the senders IP address through a RBL (such as zen.spamhaus.org).
If the senders IP is listed in the RBL, then your mail server can perform an action (usually Bounce the Message)

== Considerations ==
By implementing RBL's you are giving a 3rd party control over your mail server.
If the RBL mistakenly lists the wrong IP then '''legitimate''' mail could get bounced/rejected.
Before implementing RBL's make sure the RBL is trustworthy and builds its lists based upon your needs.
There are many RBL's available, each doing different things. Some build their lists based upon Dynamic IP ranges, others based on viruses, and others based on "Spam Traps". The bottom line is be careful!

== Postfix RBL Controls ==

To perform RBL checks in [[Postfix]] use ''reject_rbl_client rbl.provider'' under ''smtpd_recipient_restrictions'''

smtpd_recipient_restrictions =
permit_mynetworks
...
...
reject_rbl_client sbl-xbl.spamhaus.org
...
...

Its a good idea to put ''reject_rbl_client'' higher up in the list because it can eliminate the need to perform other checks which use system resources.

[[Category:Postfix]]

@@ Line 1: / Line 1: @@
-'''Real Time Blacklists'''
+'''Real Time Blacklists'''<br>
 RBL's are lists of IP addresses which are known to send SPAM.
 == How RBL's Work ==
@@ Line 11: / Line 6: @@
 Mail servers perform a dns lookup of the senders IP address through a RBL (such as zen.spamhaus.org).
 If the senders IP is listed in the RBL, then your mail server can perform an action (usually Bounce the Message)
@@ Line 19: / Line 13: @@
 Before implementing RBL's make sure the RBL is trustworthy and builds its lists based upon your needs.
 There are many RBL's available, each doing different things. Some build their lists based upon Dynamic IP ranges, others based on viruses, and others based on "Spam Traps". The bottom line is be careful!
 == Postfix RBL Controls ==
 To perform RBL checks in [http://www.postfix.org/uce.html#smtpd_sender_restrictions Postfix UCE Controls] use ''reject_rbl_client rbl.provider'' under ''smtpd_client_restrictions'''
@@ Line 30: / Line 22: @@
 This checks the senders IP early on, saving system resources.
 [[Category:Postfix]]

@@ Line 24: / Line 24: @@
 == Postfix RBL Controls ==
-To perform RBL checks in [http://www.postfix.org Postfix] use ''reject_rbl_client rbl.provider'' under ''smtpd_recipient_restrictions'''
+To perform RBL checks in [http://www.postfix.org/uce.html#smtpd_sender_restrictions Postfix UCE Controls] use ''reject_rbl_client rbl.provider'' under ''smtpd_client_restrictions'''
-  smtpd_recipient_restrictions =
+  smtpd_client_restrictions =
-     permit_mynetworks
-     ...
-     ...
       reject_rbl_client sbl-xbl.spamhaus.org
 [[Category:Postfix]]