13

It is well known that it is possible to configure a DNS server to do a "catch-all" resolving on a single subdomain level, such as *.example.com. IN A x.x.x.x, so that anything.example.com maps to a single IP/CNAME.

However, I need to set up an at least "level-2" wildcard sub-subdomain catch-all wildcard system so that any.thing.example.com or better, item.of.any.level.under.example.com will be resolved to a single IP.

Has anyone got this working?

3
  • I can just say it definitely is possible. You'll have to wait for someone competent to tell you how, though.
    – o0'.
    Jun 12, 2011 at 14:40
  • Yes, I belive it is. But I need an advice how to achieve this on common server software (BIND, Microsoft DNS server, etc.).
    – Jan Rovner
    Jun 12, 2011 at 15:29
  • You should add the DNS software that you are using
    – MichelZ
    May 22, 2014 at 10:57

3 Answers 3

7

On any real DNS server a wildcard record will match one or more labels.

See section 4.3.3 of RFC 1034.

6

Works in bind with just a record for *.dig.foo.com, it will grab anything under that domain. I.e. dog.cat.dig.foo.com

Edit:
This is a sample configuration file.

BIND 9.2.4 and the zone file content is 
$ORIGIN test.domain.com.
*          CNAME          proxyserver.domain.com.
$ORIGIN domain.com.
....
1
  • Thank you for the reply, could you please give me a BIND version number and possibly and the contents of a zone file?
    – Jan Rovner
    Jun 13, 2011 at 12:36
1

We use multi level subdomains on our CDNs. In our DNS control panel (Zerigo) we just used *.ourcdn.com mapping to a CName of our CDN. Then we can use

node1.site1.ourcdn.com
node2.site1.ourcdn.com
node1.site2.ourcdn.com
node2.site2.ourcdn.com

I haven't had a chance to test this on BIND etc. but I'm fairly certain it will work the same in there, Zerigo responsds with

*.ourcdn.com. IN CNAME cdnsource.com

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