We recently purchase Mailwise service. It is a outsdie 3rd party filtering service.
They have instructed us to lock down the incoming smtp traffic to our network so that our email can be filtered. see below:
If you would like to configure your firewall or router to accept messages only from MailWise. Our network range is 220.127.116.11/24.
Please accept the entire Class C Range (.1 through .255) as part of a trusted host
Here is my access list i created with the group.
access-list 150 permit tcp 18.104.22.168 255.255.255.0 any eq smtp
access-group 150 in interface outside
Please let me know if this will do???