Exchange 2003 user account

When i create a user in Windows Server 2003 and an exchange mailbox (exchange 2003) (Active director intergrated) the user does not show up in the global address book, the user gets an error when trying to send an email “interface not registered” the users mail box does show up in the exchange systen manager and can recieve email…everything worked fine until i had a few problems with dns so i reinstalled dns i also configured recipient filtering in exchange…any help would be greatly appreciated. Thanks