Rick - as a sysadmin who has to deal with a *lot* of spam complaints (~2500 users, "I feel your pain".

Restricting relaying as you have is a great solution, if draconian. I'm sure it will help, and still urge users to not propagate/advertise their catsailor.com addresses. The more places one "registers" the address, the more places there are to "farm" them - obviously, giving the address to a known & trusted individual is not a problem.

Yes, this is definitely unrelated to the forum or using the forum!