[Mimedefang] ANNOUCEMENT: Net::validMX v2.2.0 now available.

Kelson kelson at speed.net
Thu Jun 1 19:13:12 EDT 2006

Paul Whittney wrote:
> I had one problem with an email address from yahoo.com's
> groups, which includes an '=' inside the user portion of the email.
> I admit, this is perhaps outside the rules you made for the check_email_validity
> function, but I've got a diff if thats any help (I don't think this is a bug,
> perhaps something unique with a single system).

Actually, that's fairly common in systems that rewrite the envelope 
sender for various reasons.

VERP <http://cr.yp.to/proto/verp.txt> is a common way for mailing list 
software to work out exactly which subscribers are bouncing 
(particularly when the bounce leaves out the problem address, or the 
subscribed address forwards to another address that rejects the message. 
   They don't have to use '=' as a separator, but it's in the canonical 
example, so it's pretty common.

SRS <http://www.openspf.org/srs.html> is intended to allow forwarders to 
use their own domain on re-sent messages, but preserve info about the 
original envelope sender so that bounces from further down the line can 
get back to the right place.  Again, it doesn't have to use '=' (each 
forwarder could design its own scheme), but the reference 
implementations do.

So yeah, '=' will show up in the LHS of a significant number of legit 
envelope senders.

Kelson Vibber
SpeedGate Communications <www.speed.net>

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