When you install IMF it defaults the SCL values to 4. So when before SP2 everything was running hunky dory and both SCL values were 2. After SP2 I have had nothing but problems with employees complaining that other companies they deal with an a regular basis emails aren't getting through, etc. Even a company I do work from MoveLine.ca emails are being rejected with IMF. So I have set IMF to 4, restarted SMTP server, even tried to restart the whole server. Emails are still getting rejected, so I set IMF to 8, fewer emails are being rejected but it's only when I turn IMF off all together do the emails get through. Could Microsoft have buggered up IMF with SP2? I am not even running SecureID. Thanks Andrew