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

Suresh Ramasubramanian suresh at
Thu Dec 4 20:00:48 UTC 2003

Chris Lewis  writes on 12/4/2003 2:24 PM:
> As I understand it, they blacklist if an IP with no rDNS generates "some 
> threshold of" complaints.  Not just "no rDNS" by itself.

That is a good way to go.

> A simple "no rDNS" rule causes too much trouble with our overseas 
> customers.  I'm sure AOL discarded that idea for the same reason.

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".


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

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