Odd bind behavior with wildcards

fantasygoat · 04-18-2011, 08:12 PM

I've got an interesting problem when it comes to wildcard entries in bind.

If I put the following in:

qa.express IN A 172.16.0.10
* IN A 172.17.1.156

If I then look up "express.example.com" it doesn't return an answer - it *should* return 172.17.1.156, but it won't unless I put that hostname in specifically. qa.express.example.com resolves as expected.

Any ideas why this happens?

bathory · 04-19-2011, 03:19 AM

Hi,

I guess your zone name is example.com. With these lines in the zone file you can resolve *.example.com and qa.express.example.com
If you want to resolve express.example.com and subdomains like *.express.example.com, you need to define a new $ORIGIN

Code:

* IN A 172.17.1.156 ; for *.example.com (except express.example.com)

$ORIGIN express.example.com.
@ IN A 172.17.1.156 ; express.example.com
qa.express IN A 172.16.0.10
* IN A 172.17.1.156 ; *.express.example.com

Regards

fantasygoat · 04-19-2011, 06:21 AM

If you do an ORIGIN, don't you skip the subdomain?

Quote:

$ORIGIN express.example.com.
@ IN A 172.17.1.156 ; express.example.com
qa IN A 172.16.0.10

Anyway, I'm just curious why it doesn't work as expected given the example I've given.

bathory · 04-19-2011, 07:35 AM

This is the way dns works. You should read RFCs 1034, 4592 about domain wildcards.
If you bother reading all this stuff, have a look here and here (last paragraph)

Regards