[Mimedefang] Invalid host

[Paul]

>Hi,
>
>I've recently had to move the MX record for one of our domains. 
>Unfortunately though, some of the machines that are sending email to 
>these address, are using "internal" email addresses, and so are being 
>rejected by the mail server as not existing.

>Does anyone have any ideas where it's being rejected, and how I can get 
>around the problem.

Have you added those hosts/domains in sendmail's local-host-names file? (/etc/mail/local-host-names) I had a similar issue a while back and added the offending domain there solved the problem.

Good luck

Paul