Can DNS host records be setup to create wildcard sub-subdomains

Question

Is it possible to create a wildcard host record for a sub-subdomain ie *.foo.example.com?

Solution

Yes, in the general case. DNS supports this, bind zonefiles support this. If you're using a management UI, you'll need to check what's supported by that.

@ORIGIN example.com.
; ...
*.foo  IN A  192.0.2.1

Note that if you create another record for an item in foo, then that will stop the wildcard from providing a record. Wildcards only match where no other name matches. So you'll need to explicitly provide the data that the wildcard would have provided.

@ORIGIN example.com.
; ...
*.foo       IN A    192.0.2.1
fred.foo    IN TXT  "Fred was here"
fred.foo    IN A    192.0.2.1

Comments

[Philip]

Yes! . (15 min)

[Robert]

Thanks - that is helpful. Not sure if my registrar supports this through its UI.

[Robert]

let's hope so !