buggy nameservers resolve x.y.z CNAME a.b.c but not x.y.z. CNAME w.y.z

[jcomeau_ictx]

I've had problems for a couple of years now with certain providers not
being able to resolve www.jcomeau.com which WAS an alias to
unixshell.jcomeau.com (I've now changed it to an A record). I've been
doing some testing today, and it seems these DNS daemons balk on doing
recursive queries to the same domain.

I now got:

test.jcomeau.com. 28800 IN CNAME www.jcomeau.com.
test2.jcomeau.com. 28800 IN CNAME cosf.unternet.net.

Both of these CNAME targets point to the same server, but the first one
fails on Qwest's nameservers 206.81.128.1 and 206.80.192.1, and the
second works. If you try it within the next 8 hours, though, you'll see
cached records that confuse the issue somewhat.

Any of you who have xxx.domain.zzz CNAMEd to yyy.domain.zzz, and have
people unable to reach your site, you may be a victim of such buggy
nameservers. At least I *THINK* it's a bug... if anyone can point out
something I overlooked, please do. Thanks -- jc