[imp] Trouble with email addresses containing empty domain labels

[Jens Wahnes]

Hi,

with current stable version of Imp (6.2.17) and Horde_Smtp (1.9.4), we 
are seeing problems with emails that are to be sent to addresses that 
appear to be invalid, as they contain two adjacent dots and thus an 
empty "label" (at least that's what I would call this in DNS 
vocabulary).  To make things clearer, consider, for example, an address 
such as johndoe at example..com

When one tries to send an email to an address like that, at a certain 
point in processing that email, some Horde component seems to drop the 
domain part of the address completely. So in the example of 
"johndoe at example..com", it will try to send an email to just "johndoe" 
without any domain. Interestingly enough, the entry in the imp_sentmail 
table contains the full (wrong) address. On the other hand, the "To" 
header of the email, as saved in the "Sent" folder on the IMAP server, 
does not contain the full address, but only the localpart. Of course, 
the recipient's address given in the SMTP dialogue is lacking the domain 
as well.

So after doing some tests, I'm still unsure if Imp or Horde_Smtp or some 
other package is to be blamed.  Could someone help clarify?

Of course, there is also the question of how to best deal with this. In 
an ideal world, I'd say that Horde_Smtp should be able to deal with 
these kind of email addresses but Imp should never generate them. IMHO, 
users trying to send an email to an address with a typo like this (two 
dots instead of one dot) should receive an error message and the message 
should not be sent until they revised the email address.


Jens


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