Adrian, Aren't you making an error in reflection (Überlegungsfehler)?
If the provider on which one is guesting has a policy to block outbound access from their network to all ports used for sending of mail, so that they can force one through their SMTP server for sake of control, micromanagement, or whatever, then (assuming they know about it), would they not then block official port 587 as well as port 25? That was the position I heard the 'customer service rep' take the last time I tried to solve such a problem through appeal to bureaucratic sensibility. Of course non-standard allocation of a system port has its drawbacks, and one has to be aware that a new 'official' use might come along *and* be so wildly popular that the port might have to be freed for the official purpose. But that doesn't happen often. There are times when throwing rules at a problem doesn't add value. If the problem one is to solve is to add value for one's customers in spite of a sandbagging bureaucracy who are never held responsible for their actions, there may be no other way. At least that is the thinking of fastmail, who have done what I recommended for years. I only recommended following their example as it has been going on for so long as to be come a 'standard' non-standard. Microsoft have proceeded similarly on many occasions, and have almost always gotten away with it. Charles -----Original Message----- From: Adrian Ulrich [mailto:[EMAIL PROTECTED] Sent: Sunday, February 18, 2007 9:58 AM To: swinog@swinog.ch Subject: Re: [swinog] to SPF or not to SPF > So I would suggest offering SMTP (AUTH) support on ports 25 and 26, just to > be sure. No no no. RFC: 2476: | 3. Message Submission | 3.1. Submission Identification | | Port 587 is reserved for email message submission as specified in | this document. Messages received on this port are defined to be | submissions. The protocol used is ESMTP [SMTP-MTA, ESMTP], with | additional restrictions as specified here. | | While most email clients and servers can be configured to use port | 587 instead of 25, there are cases where this is not possible or | convenient. A site MAY choose to use port 25 for message submission, | by designating some hosts to be MSAs and others to be MTAs. Port 587 has been widely deployed: $ telnet smtpauth.bluewin.ch 587 $ telnet mail.gmx.net 587 $ telnet smtp.gmail.com 587 Inventing new ports < 1024 is just plain wrong. -- RFC 1925: (11) Every old idea will be proposed again with a different name and a different presentation, regardless of whether it works. _______________________________________________ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog _______________________________________________ swinog mailing list swinog@lists.swinog.ch http://lists.swinog.ch/cgi-bin/mailman/listinfo/swinog
