[CLUE-Tech] reverse DNS

[Angelo Bertolli]

> 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.
>
Also, what do you think about just accepting all mail, and then maybe 
not delivering it if you don't like it?  (What is the term for this?)  
This would have the effect of not only reducing the payoff of spammers 
(like with blocking), but also leaving them in the dark about which 
servers are delivering their mail, which ones aren't, etc.  But I guess 
there are legitimate reasons for mail to get bounced back... so that may 
not be a good thing.  I know one thing I have found annoying is when 
people respond with a 400 error to something that should be a 500 error, 
because they want to delay spammers as much as possible.

Also, what do you think about tar pits?  They seem kind of aggressive, 
but are they really changing anything?

Angelo