Using exchange 5.5.
SP3 installed as far as I can remember.
Currently many users have access to internet e-mail as well as internal. For some of them, I want to prevent them sending or receiving internet e-mail. I thought that I would just have to remove their internet e-mail address from the addresses tab in the properties section for each specific user. However when I tried this today, this was not enough. They could still send mail.