vixie@decwrl.dec.com (Paul A Vixie) (12/04/88)
Since it is essentially on my advice that pacbell does what it does, I'd better answer this before David gets worried... Note the Followup-To: and please respect it. [Kantor] # Nearly every one of the bounced messages turns out to be a reply to mail # that passed through host 'pacbell' before it got to ames. 'pacbell' # doesn't add its sitename to the "From:" line in mail, but does add it to # the "From " line. # [...] # The system administrator at host 'pacbell' claims he's doing the right # thing. I think he's wrong. There it stands. And I think he's right. Is that as far as we're going to get? Some sites add their names to From: lines, some don't. All (uucp) sites add their names to From_ lines. Mailers that depend on being able to send back to a From: line will run into many RFC976-compliant mailers out there that leave it in "user@dom.ain" format -- so they'd better run routers of some kind -- and many other mailers that break a perfectly good "user@dom.ain" by prepending their hostname and a bang to it, thereby creating a mixed address. Third order effects of this are far and wide -- like mailers that try to "fix" mixed addresses for you, etc. My assertions on this topic: (1) smart mail user agents or mail user agents that can depend on a smart transport (that is: elm or any user agent that knows it's talking to smail) should reply to "From:" addresses, since they _are_ supposed to be addresses. (2) dumb user agents or any user agent that knows it's talking to a dumb transport should use the From_ retuyrn-path (since it _is_ a path). (3) mailer user agents that cannot be made to do the right thing should be fixed. (4) the non-gateway transports that modify "From:" addresses should be rm'd. (5) given that some transports modify "From:" and some do not, the direction we need to move toward is getting them all (except gateways) to _not_ modify "From:". -- Paul Vixie Work: vixie@decwrl.dec.com decwrl!vixie +1 415 853 6600 Play: paul@vixie.sf.ca.us vixie!paul +1 415 864 7013