[gnutls-help] Trouble with wildcard cert on servers without FQDNs?

[Dan Kegel]

The script http://kegel.com/wildcard-bug.sh.txt demonstrates
generating a wildcard cert
on ubuntu using openssh, and using it with gnutls.  Works great on a
real machine with
a real FQDN.  But if I run it on a container without a FQDN,
gnutls-cli refuses to trust the server.

What's going on here?  Are servers only trusted if the client can look
up the server's primary name in DNS?

Sorry for the ugly script, I'm not fluent in certificates.