THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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This article describes experimental technologies used at \[http://www.junkemailfilter.com Junk Email Filter\]. I (Marc Perkel) am writing this in the hopes that other people will pick up on these ideas and improve them. Although it is working very well for us so far, it can be improved and expanded. It is my hope that this will inspire others to work on this and make it far better than what we have developed. Information about our Host Karma lists can be found \[http://wiki.junkemailfilter.com/index.php/Spam_DNS_Lists here\] |
We are all familiar with black lists. Black lists are DNS lists that where IP addresses of spammer are looked up. You send a request to the list with the IP and if it is in the blacklist then you bounce the email. Sounds simple enough except for the false positives.
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Forward Confirmed rDNS means that when the name returned by a PTR lookup is checked it will point back to the original IP address that was looked up.
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1.2.3.4 -> mail.mydomain.com |
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mail.mydomain.com -> 1.2.3.4 |
Spammers can't spoof this because even though PTR can be faked the spammer can't create an A record to point back to the original IP because they don't have control over the faked domain.
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