Questions about ANAME DNS records

Question

Shopify recently sent a link asking that I update DNS - They talk about ALIAS or ANAME records, and assert these are different to CNAME and A records.

I understand what CNAME records are, and why you don't use them for the root of the domain - and that ANAMES purport to address this shortcoming, however I do not understand how these are meant to be implemented.

ANAME Records appear to be something made up by "DNS MADE EASY", but from what I can see are not actually implemented as an RFC. Does anyone know how they work ? (Are they simply an abstraction to an A record which substitutes the ANAME with an A record, possibly providing different A records on different nameservers if there are nameservers in multiple places ?

Also, can anyone speculate as to why someone like Shopify would be pushing these (IE how do they benefit from this over using an A record - for that matter, how does it work in place of an A record on the origin of a zone ?)

Answer 1

ANAME (aka ALIAS) isn't a real record type, it's more like a template/macro that expands to A & AAAA records copied from the target domain, refreshed every hour or so.

Shopify want you to use ANAME or CNAME because they want to remain able to change their web servers' IP addresses without breaking the customers' domains. (With ANAME, they can just switch the address in their own DNS and take down the old ones after a few days. But if some customers have entered A & AAAA records directly, it could take weeks for them to notice.)

Answer 2

In internet world, for any DNS record related, a domain usually called by @ ie root for example mycompany.com. But for communicating the domain from outside you require IP (v4 or v6). So advertsing the domain IP to the external world by means of A record, called Name record. Basically it is mapping a static IP to your domain.You may seen some thing like in your hosting ISP DNS entries

@ IP Address mycompany.com IP Address

You can also use A record for creating subdomain for your domain

abc.mycompany.com IP Address1

def.mycompany.com IP Address2 etc..

Whereas CNAME record is Canonical name ie secondary name for the domain

mycompany.com can also called as ourcompany.com similarly

abc.mycompany.com also called as cba.mycompany.com

so you should have record in A section as

abc.mycompany.com IP Address1

and in CNAME section

cba abc.mycompany.com ( Here full fqdn not required for CNAME )