How can I stop my users sending mail to an external domain?
You can use the redirect file to stop users sending mail to any specific external domain. To do this go to the Incoming > Redirect page and add the following rule to the redirect file.
|Remote IP Address||1.2.3.*|
|Local IP Address||*|
|Action||Protocol Refuse with…|
|Parameter||500 Mail to external.com disallowed|
In the above example the Remote IP Address is the same IP range that you have specified under Security > Local IP
The domain that you would like to stop your local users emailing is external.com
Keywords:Stop, Filter, Redirect, Send, sending, mail outgoing