It might be interesting for IAB to think about the estimated half-life of well-known port numbers in the Internet architecture, since we've been seeing (1) firewalls that limit traversal based on port numbers, (2) ISPs that have opinions about what services go where, based on port numbers, (3) URL schemes that support alternate port numbers fairly easily, (4) Mechanisms like SOAP that use HTTP as a substrate (ne: RFC 3205) specifically to avoid (1) and (2), and (5) Servers running at alternate ports specifically to avoid (1) and (2) Knowing what "port 25" means seems like something our children won't understand... ... although they may wonder why everything EXCEPT web access is running over port 80! Spencer > -----Original Message----- > From: Theodore Ts'o [mailto:tytso@mit.edu] > Sent: Thursday, February 27, 2003 8:33 AM > To: RL 'Bob' Morgan > Cc: IETF > Subject: Re: IAB policy on anti-spam mechanisms? > > > On Thu, Feb 27, 2003 at 12:41:41AM -0600, RL 'Bob' Morgan wrote: > > Many sites, including my university, support STARTTLS+AUTH on the > > Submission port (587, RFC 2476), which I believe is the recommended > > service for clients to use to submit mail in any case (though not > > well-supported among MUAs, to my knowledge), and also is > effective at > > getting around ISP blockage of port 25. Of course if it > becomes very > > popular the misguided ISPs will block it too. > > Yup, the problem with well-known ports is that well-known port numbers > get either (a) blocked by misguded ISP's, or (b) transparently proxed > by misguided ISP's. Since I have no idea what sort of stupidity I > might encounter at various different hotel, conference, or 802.11 > hotspot networks, it's more convenient for me to use a non-standard > port.