I came across a situation where there where several users on a network that could not email out as a shared departmental name.
What I mean by that is...that sometimes they want to send and receive email to their individual email accounts. But..sometimes, the general public would email in questions to a generic email account. (Like Questions@domain.com). Each user had that same extra email address added on their computers (Outlook 2007) as an extra mailbox.
That way, multiple people would be viewing the mailbox, and no matter if someone was on vacation, or sick, the mail from the general public was always seen through this extra mailbox.
Well..a request came in to actually ANSWER some of that mail. The email was not to come from the person reading it, but from the general email account that multiple people shared in viewing.
The problem came as the email server (Called Exchange 2003), decided to DENY outgoing mail.
All users were given FULL MAILBOX Rights...but all were denied sending mail each time they tried.
SOLUTION!!
1. Start Active Directory Users and Computers; click Start, point to Programs, point to Administrative Tools, and then click Active Directory Users and Computers.
2. On the View menu, make sure that Advanced Features is selected.
3. Double-click the user that you want to grant send as rights for, and then click the Security tab.
4. Click Add, click the user that you want to give send as rights to, and then scroll down and check "send as" under allow in the Permissions area.
4.5 Remove all other permissions granted by default so only the send as permission is granted.
5. Click OK to close the dialog box.