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

Petri Helenius pete at
Wed Dec 3 16:30:21 UTC 2003

Michael.Dillon at wrote:

>Proper configuration of is a "good idea" TM.
>However, it isn't the right way for large mail server operators
>to go. Instead, they should start exchanging their SMTP sessions
>on a port other than 25, i.e. NIMTP (New Improved MTP). The NIMTP
>servers would not accept incoming connections from unknown servers.
>In order to join the club, you would have to certify that you will
>only send mail from known senders or relay mail from organizations
>which will make the same certification. In this way, we create an
>overlay mail transport network in which the members have some sort
>of one-to-one mail peering relationship that allows them to enforce
>an AUP on each other as well as maintain good contact info.
The system exactly like you describe already exists. It´s based on the 
X.400 protocol and is available across the world. Or in some parts, used to
be. If that approach would be highly successful, why would it not prosper
instead of SMTP today?


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