You're assuming that these people aren't permanently online. I expect most of our users (I hesitate to call them customers, simply because a lot of them haven't paid anything) are using 24/7 type connections. Certainly, running your own mail server and being online two hours a day is foolish.
But just the opposite, you're assuming they ARE permanently online. Even if it was a 50/50 mix, that's still quite a few.
that met your static IP standard of approval, and yet was (unless he wanted to pay extra) only online 1/6th of the time. Now, most of our users may not have static IPs, but they're most likely online 24/7 or close enough.
Which of the two uses more resources on your servers? I'm willing to bet the static IP dialup person will, so there goes your argument.
The case you state is the norm. Most dialup people who want to run mail servers use backup MX's supplied by their ISP's. If they run a mail server without proper DNS and a static address, they are no better than the untracked rogue spam mail servers that appear from throw away accounts.
Running mail servers on non-permanent dialup connections is foolish, I'll grant you that any day, but that wasn't the point you were making. Your point was that mail servers on dynamic IPs (and you never answered my question on how you define dynamic) are bad, no matter the circumstances surrounding them, and that's just plain not true.
You claim that you have 10,000+ users using dynamic DNS to run SMTP services. That being said, every one of them violate the host requirements for SMTP outlined in RFC1123. Sections 5.3.1.2, 5.3.5, 6.1.1 (keyword MUST).
Oh, and BTW, you're not benefiting our users by having your servers queue mail for our users. You're benefitting YOUR customers who presumably want to be able to send mail to our users, and who expect your servers to queue mail.
Right, but your promoting your users to run SMTP servers that violate RFC. While you claim that many of them are online all the time, you can't say for sure that they are. That and the fact that by the RFC, they violate the DNS requirements outlined. -- Robert Blayzor, BOFH INOC, LLC rblayzor@inoc.net "Unix is simple, but it takes a genius to understand the simplicity." - Dennis Ritchie