External Connection / Mail Server

Dear colleagues,

I have an internal e-mail server and in the last few days, I have received several login attempts in an attempt to send emails through IPS port 25 coming from other countries where we do not have employees. I would like to know how I could block connections from other countries only for login attempts/sending messages through our internal server.


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[edited by: emmosophos at 7:23 PM (GMT -7) on 5 Oct 2022]