I need to have a wildcard DNS record (CNAME preferred, but A/AAAA would be fine) for some dynamic services that I'll be setting up, but I don't want to start matching arbitrary records within our domain.
Specifically, I want the wildcard record to match
FOO.testing.example.com but not
BAR.example.com (having a wildcard record matching anything at all in your domain is just asking for confusion and delay). I know how to do this with BIND (and that question is already answered here), but we're using a DNS hosting service (Joker.com) whose DNS configuration web forms reject adding a record (of any kind, A, CNAME, anything) for
*.testing - so this does not seem to be possible without switching DNS providers.
On my personal domain hosted at FreeDNS, adding a second-level wildcard wasn't immediately obvious (I had to put just
testing as the domain name and then check the wildcard check-box) but it was possible. However, I'm not likely to get my organization to move their DNS hosting to afraid.org - so I'm wondering if any more mainstream DNS hosting services (or better yet, low-cost registrars that offer free DNS hosting) allow you to set up these second-level wildcards. This is not the kind of thing that really shows up in FAQs or other documents (kind of an obscure use case) so it's really hard to check this without setting up an account. I'm hoping some of you all might be able to test this out with your DNS hosting service, and answer here if they have some way to set this up.
In the meantime, I think my workaround will be to delegate the
testing sub-domain as a separate zone to the DNS hosting offered by the VPS provider that is actually providing the VMs where the service will be running, and create a first-level wildcard in that domain. It's a lot of machinery for something that should be pretty simple and not actually require a delegation, but I'll be able to make it work without involving any bean counters...