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

Suresh Ramasubramanian suresh at
Wed Dec 3 15:25:57 UTC 2003

Christopher X. Candreva  writes on 12/3/2003 10:13 AM:

> Since I'm 99% sure the idea (or stupidity thereof :-) of blocking SMTP
> servers without reverse DNS came up here in this discussion, I just ran a
> manual queue run to clean out a queue, and saw this come up:

They have had this policy since several months now but it is still a 
"may" - and does give them a good excuse to take out large IP blocks 
that don't have proper reverse DNS assigned and emit a lot of spam.

More at

If this is what it takes to push more people to get valid PTR records on 
their mailservers ...

> I don't know if this is new -- I don't recall seeing it before, but it
> doesn't say they WILL refuse, just they may. If they do start blocking --
> this WILL be an operational issue.

Lots of mailservers (such as the one for already do this.

I have not seen any large ISP other than AOL do this yet, though. 
However if they make it a "must" rather than a "may", I can see a whole 
lot of ISPs who will be quite eager to follow suit and do something on 
the same lines.


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

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