I have a legacy SCO 5.0.6 server that sends various alert/informational messages to my Exchange 2003 SP2 server. If the FROM: field is a non-existent user, bogus@mydomain.com or bogus@sco.mydomain.com, Exchange accepts them and delivers them correctly. If the FROM: field is a valid Exchange user, bigboss@mydomain.com, the message is dropped or sent to the UCE archive, depeding on how the Sender Filtering options are set. I have all my valid users in the Sender Filtering list to help prevent spam. However, I must leave bigboss out of the Sender Filtering list because of the message sent from the SCO Sendmail. If the bigboss is the Sender Filtering list the message are dropped. How can I allow those message from bigboss@mydomain.com from the SCO system to be delivered correctly while leaving bigboss in the Sender Filtering list to prevent spam. I've asked the programmers to change the FROM address on those emails, but I'm so far down the priority list, I don't know when it will happen. Brantley Allen System Administrator

The simple way is to create a second SMTP virtual server, and don't enable filtering on it. Then ensure that the recipient whitelists the sender. You will either have to use another port, or another internal IP address. As long the port or IP address isn't exposed to the Internet, it cannot be abused. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Hi, How troubleshoot is going on?Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread. Thanks Gen Lin-MSFT