[Exim] Is 'rcpt to: <domain.tld.>' legal (note trailing dot)…

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Author: Marc MERLIN
Date:  
To: exim-users
Subject: [Exim] Is 'rcpt to: <domain.tld.>' legal (note trailing dot) ?
I was investigating a mail bounce and the sender and I investigated several
mailers:

----------------------------------------------------------------------------
> kenny:~# telnet kenny smtp                                                     
> Trying 10.1.3.166...                                                           
> Connected to kenny.su.valinux.com.                                             
> Escape character is '^]'.                                                      
> 220 mail.valinux.com ESMTP Exim 3.16 #1 Wed, 23 Aug 2000 18:29:19 -0700 - VA   

mm1                                                                              

> mail from: merlin@???                                                  
> 250 <merlin@???> is syntactically correct                              
> rcpt to: merlin@???.                                                   
> 501 merlin@???.: domain missing or malformed                           


Most interesting, it appears this is a bug/mis-feature in the submission         
software of the original message. Witness sendmail though:                       


marine[~] $ telnet 0 smtp # sendmail                                             
220 marine.au.int.en-bio.COM ESMTP Sendmail 8.11.0/8.11.0/Debian 8.11.0-1; Thu,  
24 Aug 2000 11:41:49 +1000                                                       
[snip]                                                                           
mail from: <akumria@???.>                                   
250 2.1.0 <akumria@???.>... Sender ok                       
rcpt to: <akumria@???.>                                     
250 2.1.5 <akumria@???.>... Recipient ok                    


marine[~] $ telnet mail.aphid.net smtp # postfix                                 
220 giardia.yourweb.com.au ESMTP Postfix                                         
[snip]                                                                           
mail from: <jdub@???.>                                                     
250 Ok                                                                           
rcpt to: <jdub@???.>                                                       
250 Ok                                                                           


marine[~] $ telnet qmail.org smtp # qmail                                        
220 ns.crynwr.com NO UCE ESMTP                                                   
[snip]                                                                           
mail from: <akumria@???.>                                                
250 ok                                                                           
rcpt to: <postmaster@???.>                                                 
553 sorry, that domain isn't in my list of allowed rcpthosts (#5.7.1)            
rcpt to: <postmaster@???>                                                  
250 ok
----------------------------------------------------------------------------


I know how to tell exim not to check the To: field. I may even be able to do
rewriting at the SMTP level to remove the dot, but the question is should I?

RFC 822 isn't detailled enough to say (the BNF doesn't describe what atom is
supposed to be like)

Marc
--
Microsoft is to software what McDonalds is to gourmet cooking

Home page: http://marc.merlins.org/ (friendly to non IE browsers)
Finger marc_f@??? for PGP key and other contact information