[Spamassassin Wiki] Update of "Rules/RDNS DYNAMIC" by LeeMaguire

[Apache Wiki <wi...@apache.org>]

Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Spamassassin Wiki" for change notification.

The following page has been changed by LeeMaguire:
http://wiki.apache.org/spamassassin/Rules/RDNS_DYNAMIC

New page:
#language en
== SpamAssassin Rule:  RDNS_DYNAMIC ==

''Standard description:'' Delivered to trusted network by host with dynamic-looking rDNS

=== Explanation ===

The reverse DNS of the last untrusted relay is checked, if authentication is not used, against a number of rules that attempt to determine if the IP address is static, or dynamically allocated.  Legitimate mail servers would usually be expected to have static allocations.

There are no widely adopted standards for indicating the allocation type in reverse DNS, however it is possible to interpret the naming conventions used by some sites to derive this information.   Reverse mapped names that contain sections matching strings such as "dynamic", "dhcp", "adsl" etc. may be matched by this rule, as may names that contain strings of numbers.

=== Further Information ===

The default scores for this rule can be found [http://spamassassin.apache.org/tests.html in the online list of tests].

The IETF's [http://www.ietf.org/html.charters/dnsop-charter.html dnsop] working group
has a draft memo regarding a [http://tools.ietf.org/html/draft-msullivan-dnsop-generic-naming-schemes-00 suggested naming scheme]
and a draft memo regarding the [http://tools.ietf.org/wg/dnsop/draft-ietf-dnsop-reverse-mapping-considerations/ use of reverse DNS for testing].

----
CategoryRule