Re: My Newly Expanded DNS Blacklist - Who wants to try it?

[Marc Perkel]

John Rudd wrote:

If you're going to do this, I would suggest that instead of counting 
to X hits on your low priority MX's and then blacklisting the IP, do 
this:

Count on all of your MX's, and look for a ratio between "hits on low 
priority MX's and hits on high priority MX's".

IF the high priority MX hit rate is 0, then just do a simple count on 
the hits against the low priority MX's.

IF the highr priority MX hit rate is > 0, then do (low priority hit 
rate) / (high priority hit rate), and look for a number >= something 
like 10.


That way, senders that might sequentially try your servers, due to 
problems, or even just because they roll through the servers over 
time, wont get tagged.


That's a good suggestion. You have me thinking. I'm using Exim and it 
has the RateLimit logic. Rather than a ratio I could maybe create a time 
window where if they hit the proper MX then it bypasses the improper MX 
tests for a fixed number of seconds.