Hi guys-- Over the past few weeks I've been bringing my first ISA server on line. Yesterday I started using it with a test Exchange server. It seems to be working pretty well, but when mail goes through the ISA server, errors get generated in the Application Log (even though the messages do go through): Source: SmtpEvt Event ID: 20031 Description: An unknown SMTP command I looked it up at EventID.net and it referred me to Q322234. I looked at that and it says: "This message is logged when the SMTP Filter service in ISA Server receives a command that is not listed under the SMTP Commands tab in the SMTP Filter properties. The command that was passed appears in the DATA section of the event message. If the command was expected, you must add this command to the SMTP Filter properties SMTP Commands tab." The data says (amongst other gibberish): XEXCH50 and 2184. Do I need to add an "XEXCH50" command to the SMTP filter? What max length? Thanks, Rob