I am having trouble with MS Exchange 5.5. Users are able to send email and receive messages generated within the building. No outside email is getting through. Can see outside message info in tracking log, but it never gets to individual mailboxes. Running NT 4.0 on Exchange Server. Outlook for clients. It almost seems like trouble started just after loading latest security fix from WindowsUpdate on 6-4-02. Uninstalled that fix and rebooted, but did not resolve. Any thoughts are welcome and appreciated!!!!!!! Nancy