Ive had a hard time pinpointing this problem. I have various customers complain everyonce in a while that they will try to send mail and they will get a 553 sorry, that domain isn't in my list of allowed rcpthosts error. Ive tried to replicate it, but i cant. Ive noticed sometimes the timestamp on their ip on the relay table is not getting updated. Has anyone else experienced this? Recommend how to fix it?