Re: [Asrg] What are the IPs that sends mail for a domain?

[Franck Martin <[e-mail]>]

Sure, it is the the be strict in what you send, lenient in what you receive.

If we don't specify some RFC/BCP to specify how SMTP over IPv6 should be negotiated, then no one will follow.

We could say something like all emails on IPv6 must have a DKIM signature, have RDNS helo, etc... as there is not much of an implementation with IPv6, there is a chance for these practices to be adopted from day one...


----- Original Message -----
From: "Bill Cole" <[e-mail]>
To: "Anti-Spam Research Group - IRTF" <[e-mail]>
Sent: Tuesday, 16 June, 2009 10:14:02 PM GMT +01:00 Amsterdam / Berlin / Bern / Rome / Stockholm / Vienna
Subject: Re: [Asrg] What are the IPs that sends mail for a domain?

Franck Martin wrote, On 6/16/09 11:33 PM:
> Knowing that mail servers are not deployed on IPv6, what would it take to
> make all these requirements mandatory for IPv6 and start with a better
> infrastructure than on IPv4?

How do you make anything mandatory on the net?

RFC 821 is one of a handful of Internet Standards, and it is violated 
routinely by spammers and non-spammers for no better reason than that they 
never bothered to read it. That is possible because the major MTA's are 
functional when misconfigured (e.g. with a bogus name for EHLO/HELO use) and 
by default tolerate clients which violate standards.

The only way anything can be functionally mandatory for email transport is 
if major MTA's will not work unless configured to comply and by default will 
not interoperate with clients that do not comply. RFC's are great, but they 
do not enforce themselves. If the big freemail providers and sites running 
Sendmail, Exchange, and Postfix generally accept mail from non-compliant 
clients, there will be a lot of non-compliant clients. To make good behavior 
mandatory, bad behavior has to break with enough frequency that it's easier 
to comply than negotiate exemptions.