I'm doing my first mail server config on Ubuntu 16.04. In all tutorials and How-To's there's the
mail.example.com. I'm wondering if this is some formal requirement or just an example of a possible solution that is required by no standards.
I'm trying to do it with these DNS records:
MX main.dom main.dom 1 14400 CNAME www.main.dom main.dom 43200 A main.dom XXX.XXX.XXX 3600
I'm not sure how I can test it. Nor can I predict the consequences for the lack of experience. I can tell the server itself is responsive to telnet on port 25, giving this:
$ telnet main.dom 25 Trying XXX.XXX.XXX.XXX... Connected to main.dom. Escape character is '^]'. 220 server1.main.dom ESMTP Postfix (Ubuntu)
main.dom is not the real address, just a structural representation. When called on localhost
127.0.0.1, but the FQDN stays the same (3 parts).
Answers to this are hard to find on the net. And assuming I use the
MX main.dom mail.main.dom 1 14400
do I also need to create a corresponding CNAME?