Re: Empty 5322.From address or 5322.From address containing <>

[SM <sm@xxxxxxxxxxxx>]

Hi Rolf,
At 01:56 16-04-10, Sonneveld, Rolf wrote:
> The real problem here is that mail software from a recipient, that 
> validates the headers of a message, might reject the message, which 
> means a double-bounce (as we're talking here about invalid headers 
> of notification messages causing a reject). For instance the mail 
> adapter in SAP is such an SMTP server implementation which reject 
> these type of messages at the end of the DATA phase, after the 
> single dot. And we can't really blame SAP for this, after all why do 
> we have standards?

The rejection at the end of the DATA phase won't cause the SMTP 
server to generate a bounce.  The DSN is generated by the SMTP 
sender.  There are two possible problems.  I'll use Section 6.4 of 
RFC 5321 for the easier one which is invalid headers:

  'Unfortunately, variations, creative interpretations, and outright
   violations of Internet mail protocols do occur'

  'The debate as to whether a well- behaved SMTP receiver or relay
   should reject a malformed message, attempt to pass it on unchanged,
   or attempt to repair it to increase the odds of successful delivery
   (or subsequent reply) began almost with the dawn of structured
   network mail and shows no signs of abating.  Advocates of rejection
   claim that attempted repairs are rarely completely adequate and that
   rejection of bad messages is the only way to get the offending
   software repaired.  Advocates of "repair" or "deliver no matter what"
   argue that users prefer that mail go through it if at all possible
   and that there are significant market pressures in that direction.'

The second possibility is discussed in RFC 3464.

Regards,
-sm