Monday, March 27, 2017

ANAME / CNAME

An A-Name record is a domain that points directly to an IP Address. A CNAME is an alias record that points to another domain. This allows two domains to share an IP Address. If there's ever a problem with the IP chosen, the IP Address can be changed immediately with no problems.

If using an ANAME record, my.Foo.com would point to 1.1.1.1 and my.Bar.com would point to 1.1.1.1 to share IP Addresses. If you want my.Bar.com to point to a new IP Address, it can be a huge pain. With CNAME, my.Foo.com could point to subdomain1.myregistrar.com, which points to 1.1.1.1. my.Bar.com can point to subdomain2.myregistrar.com, which points to 1.1.1.1. When I want Bar.com to go somewhere different, I have control of subdomain2.myregistrar.com so that's an easy change.

The downside here is that according to the DNS specifications, Root Domains (like foo.com or bar.com) can't be CNAME records.

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