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Re: AOL rejecting mail from IP's w/o reverse DNS ?

  • From: Suresh Ramasubramanian
  • Date: Thu Dec 04 17:45:12 2003

Petri Helenius  writes on 12/4/2003 5:36 PM:

Yup. The model can be extended to "if no rDNS, and if spamtrap hits or other spammish behavior noted from more than X IPs per /24, then block the /24".

And why would blocking the /24 be appropriate instead of matching the registry?
I would refer you to the huge number of netblocks out there that stay at /16 or larger size, with the upstream not SWIP'ing or otherwise delegating netblocks in APNIC (or wherever, such as an rwhois server) as they provision IPs.

srs (postmaster|suresh) // gpg : EDEDEFB9
manager, security and antispam operations