User has sent the mail using the additional mailbox name in the From address field, but when the receipient has received the mail from address is showing blank Both the mailboxes are there in the exchange 2003 environemt but in different mailbox servers and mailbox access has been properly provided Example From : Sent : Wed, Sep 14 , 2011 time will show To : Receipient Name Subject: Subject of teh mail Mesaage body content Like this all the information will be available except the From address Header information will also shows blank

Please do a message tracking or enable smtp logging and check from where is the mail coming from before digging into exchange