Question on "Mail delivery servers" and server groups

Question

Hi, 
 I would like to have round robin delivery from the Sophos appliance to our internal mail servers. When configuring the Mail Delivery Service group, it says the DNS type is "MX". 
 How is this working? If I have entered 2 servers in the list via IP address, how is Sophos using MX records to finish internal delivery to my servers? 
 Any clarity on how inbound SMTP flow works with mail delivery server groups would be very helpful. 
 
 Thanks, 
 1/2M

GtVYU · Accepted Answer

When you set up a mail delivery server group you are able to set the priority of each server. For round robin delivery this priority should be the same for all servers in the group. 
 Once that is set up, when you associate a domain with the group under Configuration > Routing > Mail Domains , the appliance will then load balance amongst the server group. 
 As an example, I create a group with two servers: 
 Description: Test 
 1.1.1.1 priority 10 
 2.2.2.2 priority 10 
 Then I associate the domain I want with that group 
 Incoming mail domain name: example.com 
 Deliver to the following server or group: test 
 Now, mail destined for example.com will alternate between 1.1.1.1 and 2.2.2.2 
 
 I hope this helps!