On Fri, 19 Jun 2009, Jeroen Wunnink wrote:
1. Customers remember it more easily 2. Some ISP's also block 587 (hence 'SMTP ports' rather then 'SMTP port' in my previous comment ;-)
Those same clueless ISPs will probably block 2525 someday too, clueless expands to fill any void. And using non-standard things like 2525 only lead to more confusion for customers later when they try someone else's non-standard choice, e.g. port 26 or 24 or 5252 and wonder why those don't work. On the other hand, why don't modern mail user agents and mail transfer agents come configured to use MSA port 587 by default for message submission instead of making customers remember anything? RFC 2476 was published over a decade ago, software developers should have caught up to it by now. Imagine if the little box in Outlook and Exchange had the MSA port already filled in, and you only needed to change it for legacy things.