Strange behaviour resolving CNAME's via a forwarder.
Adam Goodall
adam.goodall at gmail.com
Wed Apr 20 09:19:02 UTC 2011
Hi
I am having a strange problem and I'm not sure if i am hitting a bug or
expected behaviour.
Server A on 10.1.1.1 is running BIND 9.7.0-P2-RedHat-9.7.0-5.P2.el6_0.1 on
RHEL6. It is acting as a recursor for its clients and also has a number of
forward zones configured as follows:
zone "testdomain.com" in {
type forward;
forwarders { 192.168.1.1; };
forward only;
};
Server B is on 192.168.1.1 and runs Power DNS, it is authoritative for
testdomain.com and will not service recursive queries.
Some sample entries from that zone are:
ftp IN CNAME www
www IN A 192.168.5.5
mail IN CNAME mail.someotherdomain.com.
If a client queries server A for www.testdomain.com (type any), the request
is forwarded on to 192.168.1.1 and resolves as expected.
If a client queries server A for ftp.testdomain.com (type any), the request
is forwarded on to 192.168.1.1 and resolves as expected.
However if a client queries server A for mail.testdomain.com (type any) the
request is not answered. From the logs on server B i can see that server A
is only forwarding on a request of type A. As an A record for
mail.testdomain.com does not exist on server B it does not resolve.
If i then specifically query Server A for mail.testdomain.com of type CNAME,
it resolves as expected. Subsequent requests against server A for
mail.testdomain.com of type any then resolve, presumably because it is
already in the cache.
Hopefully that makes sense! Has anyone had a similar issue and did you come
up with a work around? Is this expected behaviour or a bug?
Thanks for your help on this - its driving me mad!
Adam
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.isc.org/pipermail/bind-users/attachments/20110420/1b5ca010/attachment.html>
More information about the bind-users
mailing list