I am using exchange server 2003 and I have about 8 mailbox users. I want to be able to grant them "send as" permissions. I have followed all of Microsfts "how to" guides to set this up. I have setup the mailbox store with a group called MailBoxAcces in which all users are a member of and have "send as" permissions. In addition I have added this group as well as individual users (for testing purposes) to each users security tab (In Active Directory Users And Computers). I still get a message stating that the sender does not have permission to send an email as another user. If I turn "on behalf of" on it seems to work but I need the "send as" feature to work. I have been working on this for over a day now if anyone can help to point me in the right direction I would appreciate it greatly.