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Re: I-D Action:draft-klensin-rfc2821bis-10.txt

2008-04-15 15:05:44


gee, I don't know... if current practice is to require that senders have A or MX records, maybe we ought to insist on it in the standard. I mean, isn't the purpose of the standard to dictate current practice?

and isn't this the sort of change that should cause a recycle to proposed?


seriously, why is this the sort of bug that should dictate a change to the standard, whereas the problems associated with fallback to address records are the sort of bug that should be encouraged by the standard?


Arnt Gulbrandsen wrote:

I agree that the wording in -10 reflects the rough consensus.

However, I think 2821bis needs a little extra text to notify operators that they may need to upgrade or reconfigure to comply with 2821bis. For example currently refuses mail from AAAA-only addresses:

$ vrfy -vv -S test(_at_)ipv6(_dot_)l(_dot_)google(_dot_)com 
rcpt 'jklensin(_at_)jck(_dot_)com' at ''
connecting to ( port 25
<<< 220 ESMTP Exim 4.34 Tue, 15 Apr 2008 12:39:35 -0400
<<< Hello []
<<< 250-SIZE 52428800
<<< 250-8BITMIME
<<< 250-AUTH CRAM-MD5
<<< 250 HELP
MAIL From:<test(_at_)ipv6(_dot_)l(_dot_)google(_dot_)com>
<<< 250 OK
RCPT To:<jklensin(_at_)jck(_dot_)com>
<<< 550-Verification failed for <test(_at_)ipv6(_dot_)l(_dot_)google(_dot_)com>
... has only an AAAA RR. The same test works when I use test(_at_)www(_dot_)l(_dot_)google(_dot_)com as sender address.

(I tried some other recent posters. Some accept mail from test(_at_)ipv6, including Dave, some others don't, including you and me.)

Exim users can comply by disabling the sender_verify variable, postfix users can disable reject_unknown_sender_domain, I don't know the relevant variable for any other MTAs.