Ambiguous def of multiple CNAME

[Christine.Tran at east.sun.com]

>> server.foo.com.	IN	CNAME	server.blat.com.
>> I am almost sure it's not kosher, but so far it's worked.  I'm on BIND8.2p1.
>
>You certainly can.  we've done that for web.domain.com vs. www.domain.com vs.
>www.domain.net, etc.  

Sure, we do the same for our .com, .net and .org but I thought I read somewhere that stuck in my mind that to CNAME to a target outside of your control is to invite trouble because that target can move without you knowing.  If I CNAME frame.foo.com to frame.cnn.com., and one day they decide to change it to frameserver.cnn.com., I'm doomed.

I have an internal server authoritative for foo.com

frame.foo.com.	IN	CNAME	frame.cnn.com.

I use a forwarder.  When I look up frame.foo.com., I time out.  My debug shows me finding frame.foo.com as frame.cnn.com. and the query is forwarded.  I expect an A RR back, but instead, I get a referal to the NS RR of cnn.com.  So my internal server tries to contact ns.cnn.com, which it can't, being internal and roped off from the world. 

However, if I first lookup frame.cnn.com. my query is forwarded and answered, and I cache the response.  Now if I look up frame.foo.com, I get an answer.  The repeats when the TTL for frame.cnn.com times out.  Why this disparate behavior?

CT