ALIAS records are the answer to that quirky DNS problem of not being able to reliably CNAME your “naked” domain (a.k.a. “zone apex” a.k.a. “root domain”).
Put simply, if you’ve ever had the need to create a record like:
mystartup.io CNAME username.github.io
so that your sexy top level domain aliases another hostname, then you may have also read that this isn’t a great idea.
Unfortunately, due to limitations in the DNS specification this can cause things to go awry since the spec requires the zone apex to be an A record — that is, one or more static IP addresses. That can be a bummer since you have no control over the answers from the other service’s A records, and they may change frequently and without your knowledge — requiring you to do a bunch of manual syncing.
Enter the ALIAS record: with it, you now get the best of both worlds — the ability for your zone apex to refer to another record’s static IP list while still staying RFC compliant. An ALIAS is just a CNAME that masquerades as an A record. The best part is, when the underlying A records change, yours will stay in sync automatically.
To get started, just create your ALIAS record (either via our portal or REST API) and specify the hostname you’d like to ALIAS against — just the same as if creating a CNAME. Our service does the rest by internally resolving that address and returning the corresponding A records.
By the way, although using ALIAS records at the zone apex is the common use case, you can create an ALIAS record for any record in your zone.
Give it a shot and let us know what you think!