I have read that I "must not" use CNAMEs in MX record entries.
My in-house mail server is connected to the internet with a provider where the IP changes every two/three months. I have a subdomain
mail.mydomain.com set up which I later reference in my MX entries
mydomain.com IN MX 10 mail.mydomain.com. I am the only one in my organization who knows how to do this. When I was gone a couple of days ago the IP changed and obviously mails were not reaching the mail server.
I then thought I would solve my problem with something like CNAME and dyndns. My router would automatically update the dyndns-information and I would change
mail.mydomain.com from an
A entry to a
CNAME (pointing to my dyndns address) and be done with it. The MX entries would stay the same, pointing to the subdomain.
I have implemented this solution and it works fine, except for one specific mail server (of which I know), who apparently can't resolve the domain name. It can if I use an
Is there a "correct" way of doing this? Without enlisting the services of someone like zoneedit?