[CLUE-Tech] reverse DNS

[Charles Oriez]

At 09:49 AM 9/13/2004, Angelo Bertolli wrote:
>Anyone want to comment on RFC 1123?
>
>http://www.faqs.org/rfcs/rfc1123.html
>
>"However, the receiver MUST NOT refuse to accept a message, even if the 
>sender's HELO command fails verification. " - 5.2.5


I would say that it is trumped by the later RFC 2821

http://www.faqs.org/rfcs/rfc2821.html

"It is a well-established principle that an SMTP server may refuse to 
accept mail for any operational or technical reason that makes sense to the 
site providing the server."

Rejecting for invalid rdns rather than waiting for the dnsbl to tell the 
receiver to reject it saves on cpu cycles on the receiving server.  That is 
the same reason that I put the most prolific spammers in my access.db with 
a reject instruction - no bandwidth wasted waiting for a remote db to tell 
me what I already know.


--

Charles Oriez     coriez at oriez.org    39  34' 34.4"N / 105 00' 06.3"W
"Drag God into politics, and you'll ruin his reputation in no time." -- 
Molly Ivins