my english is very bad! maybe you misunderstood my mind
In exchange I have a lot of mail group mail for each branch. I do not want the external mail address to send this mail group. because this group mail only for internal.
Hi and welcome aboard, what you are trying to do is stop the external mail users from having access to your global address list?
Are your external mail users part of your mail system? I suspect not, so the issue is really how you advertise your global address list, so it is not available beyond your domain. My mail ability is sadly lacking in going beyond defining what I see to be the problem.
On the 'Anti-Spam' tab of 'Mail Security >> SMTP', add your Distribution List addresses to 'Expression Filter'.
On the 'Exceptions' tab of 'Mail Security >> Quarantine Report', add your Distribution Lists to 'Mailing list address patterns'.
Emails from outside will be quarantined and each person on the Distribution List will be able to release a personal copy if desired.
Cheers - Bob
PS Ian's comment is insightful. Maybe, you can change the Distribution Group names and get the company president to issue a security order that group addresses should not be given to non-employees.
Sophos UTM Community Moderator Sophos Certified Architect - UTM Sophos Certified Engineer - XG Gold Solution Partner since 2005
I didn’t advertise the distribution list address to outside of the domain. But the problem is that there’s someone who is outside of the domain got the address of the group mail and sent spam mails to the group mail. Could you please instruct me how to stop all those mail address sent to the internal group mail from outside. For the matter that you have showed me, it didn’t work well.
Let us try a different approach. The only way someone can resolve group email addresses if they are setup correctly as groups and not email distribution is to either have a mail address on your server or you have a hole which is letting them into your server.
