v2015-11-15
This file was originally created and maintained by Stan Hoeppner, and is now co-maintained by Steve Jenkins until Stan is ready to take it over again.
If you have suggested modifications to this file, please create a pull request here on GitHub so I can review and merge the proposed changes. You can use the History function here on GitHub to see the most recent changes.
Stan's original README for this file:
The following set of regular expressions attempt to stop bot spam connections by matching the FQrDNS name of the sending IP against known consumerish rDNS patterns or other rDNS patterns likely to be sources of bot spam and not legit email. This methodology is not without error, but time has proven it to be very accurate. If it blocks a sender you know to be legit and from whom you need to receive mail I recommend whitelisting that source instead of removing an expression below as a means to solve the problem. The expressions are POSIX regular expressions and can be used with either the PCRE or REGEXP table type. The PCRE engine is typically faster.
This file is provided AS IS with no WARRANTY. It is free software, without attribute or copyright, and without license. As such, you are completely free to use it and modify it as you see fit, for your purposes, with absolutely no strings attached.
Usage:
Save this file as /etc/postfix/fqrdns.pcre Add to main.cf
smtpd_client_restrictions =
...
check_reverse_client_hostname_access pcre:/etc/postfix/fqrdns.pcre
...
or
check_client_access pcre:/etc/postfix/fqrdns.pcre
Use the first above with Postfix 2.6 or later, the second with 2.5 and ealier. If you use the "everything under smtp_recipient_restrictions" style of main.cf add this toward the very top of your restrictions list, with your IP whitelist first, such as:
smtpd_recipient_restrictions =
permit_mynetworks
permit_sasl_authenticated
reject_unauth_destination
check_client_access hash:/etc/postfix/whitelist
check_reverse_client_hostname_access pcre:/etc/postfix/fqrdns.pcre
...
If you add a pattern which isn't currently covered please email it to stan at hardwarefreak.com create a pull request here so I can add it to the "master" file located at http://www.hardwarefreak.com/fqrdns.pcre review and merge the proposed changes.
The file doesn't change very often so a wget every two weeks is usually sufficient. Each file change is normally one or more new expressions or minor fixes.