It can be anything! An apex, subdomain, or even a URL.

Results forincoming-mail.aa.net.uk

Resolver

Location

A

Name	TTL	Value
incoming-mail.aa.net.uk	3600	90.155.62.28AAISP / Andrews & Arnold Ltd
incoming-mail.aa.net.uk	3600	90.155.62.29AAISP / Andrews & Arnold Ltd

Name	TTL	Value
incoming-mail.aa.net.uk	3600	2001:8b0:0:62::28AAISP / Andrews & Arnold Ltd
incoming-mail.aa.net.uk	3600	2001:8b0:0:62::29AAISP / Andrews & Arnold Ltd