X-Git-Url: https://git.exim.org/exim-website.git/blobdiff_plain/173589b215261d4e4dee1aeac8e15d3c9984f3f1..8b5a2b1aeffc5210ce494ec03d114425a076db2f:/howto/rbl.html diff --git a/howto/rbl.html b/howto/rbl.html index e35327a..614ba0f 100644 --- a/howto/rbl.html +++ b/howto/rbl.html @@ -1,16 +1,17 @@ - HOWTO - Using the RBL + HOWTO - Using DNS Block Lists (DNSBLs) -

HOWTO - Using the RBL

+

HOWTO - Using DNS Block Lists (DNSBLs)

The MAPS (Mail Abuse Protection System) RBL (Realtime Blackhole - List) is a means of identifying hosts that have been associated - with the sending of spam mail. A full description of the service - and the technology and ethics behind it can be found at http://www.mail-abuse.org/rbl/ along with more general mail policy information at http://www.mail-abuse.org/.

@@ -18,25 +19,59 @@

In the few years since MAPS started operating, other similar services although with different aims, procedures and reliabilities have been introduced - MAPS itself has a number of - these (ie MAPS/DUL which maintains lists of dial up modems), the - other major source was ORBS, - which is a more proactive relay blocking service, however this has - recently closed down. For this reason the examples now use RSS - from mail-abuse.org in place of ORBS

- -

Exim can use the MAPS RBL and/or any other similarly defined - service (ie you could make your own additional maps as well). To - use exim for this you need to be running version 1.80 or later, - the configuration example in this document are specifically for - version 3.00 and later - the old version of this document, - covering older versions of exim can be found here.

- -

Exim RBL Support

+ these (ie MAPS/DUL which maintains lists of dial up modems). At + this point in time there are many 10s of services with varying + charters - lists of these can be found at http://relays.osirusoft.com/ + and http://spamblock.outblaze.com/spamchk.html. + The services are now normally referred to as a DNS Block List + (DNSBL), rather than RBLs, however you will find that earlier Exim + documentation (ie for version 3.x) will use the older term.

+ +

Exim DNSBL Support

Exim has supported RBL from version 1.80, although the flexibility was increased (with a related change configuration - options) on the release of Exim 3.00

+ options) on the release of Exim 3.00. With the release of Exim + 4.00 the whole basis of policy checks on incoming mail changed + to be based on a set of Access Control Lists (ACLs) applied at + various during the incoming mail transaction. For this reason + the configuration of Exim 4.x and later to use DNSBLs is + complete different to that used for earlier versions.

+ +

Exim 4.x DNSBL Usage

+ +

In Exim 4.x a DNSBL lookup can be used in any of the incoming SMTP + ACLs. However it is typical for the lookups to be used in the ACL + handling RCPT TO - this allows policies to accept mail + for postmaster or other special local parts (for + example so a blocked sender can talk to the local postmaster + about getting blocks lifted or excluded)

+ +

The use of DNSBLs is substantially documented in the main exim + specification or the 4.x versions, so will not be covered in + detail here. However a couple of examples can be given

+ 
+  # Add a warning header if the sending host is in these
+  # DNSBLs but acccept the message (or rather leave it for
+  # later ACLs to accept/deny
+  warn message = X-blacklisted-at: $dnslist_domain
+       dnslists = blackholes.mail-abuse.org : \
+                  dialup.mail-abuse.org
+
+
+
+  # Reject messages from senders listed in these DNSBLs
+  deny dnslists = blackholes.mail-abuse.org
+
+ +

Documentation on these features can be found in the + specification section on + Exim @@ -91,6 +126,6 @@ rbl_log_rcpt_count # log recipient info of accepted RBLed messages

Nigel Metheringham
-

$Id: rbl.html,v 1.3 2001/05/10 11:24:39 nigel Exp $

+

$Id: rbl.html,v 1.4 2001/11/05 21:45:26 nigel Exp $