Hi All, I have a Exchange 5.5 with SP 4 on top of Windows NT SP 6. I want to restrict certain users from sending mails to some domains. I know in IMC i can block the whole domain. i don't want to block the whole domain . i want that from inside to outside some of the users should not be able to send mails to certain domains. So is it possible with normail exchange server or do i have to use any third party content based filtering tool. if somebody has done this please help me.......... With Best Regards, Vijay Dogra.