Name resolution broken after upgrading to FC5

[Cedric Tefft]

Hi all -

After upgrading my server from FC3 to FC5, it appears name resolution is 
broken in a way that I would have previously thought was impossible.  
DNS itself appears to be functioning normally (the dig, nslookup and 
host utilities work flawlessly).  However, many, though not all programs 
act as if DNS is broken -- i.e. they will resolve hosts that appear in 
the local hosts file, but nothing else.

A few examples:

-------

raven:~ > host pop.west.cox.net
pop.west.cox.net has address 68.6.19.2
raven:~ > nslookup pop.west.cox.net
Server:         192.168.1.1
Address:        192.168.1.1#53

Non-authoritative answer:
Name:   pop.west.cox.net
Address: 68.6.19.2

raven:~ > fetchmail
fetchmail: couldn't find canonical DNS name of pop.west.cox.net 
(pop.west.cox.net)
fetchmail: Query status=11 (DNS)
raven:~ >

-------
raven:/etc/yum.repos.d > host fedora.redhat.com
fedora.redhat.com has address 209.132.177.50
fedora.redhat.com mail is handled by 10 mx1.redhat.com.
fedora.redhat.com mail is handled by 20 mx2.redhat.com.
fedora.redhat.com mail is handled by 30 mx3.redhat.com.

raven:/etc/yum.repos.d > nslookup fedora.redhat.com
Server:         192.168.1.1
Address:        192.168.1.1#53

Non-authoritative answer:
Name:   fedora.redhat.com
Address: 209.132.177.50

raven:/etc/yum.repos.d > lynx -dump 
http://fedora.redhat.com/download/mirrors/fedora-core-5

Looking up fedora.redhat.com
Unable to locate remote host fedora.redhat.com.
Alert!: Unable to connect to remote host.

lynx: Can't access startfile 
http://fedora.redhat.com/download/mirrors/fedora-core-5

-------

What works: FTP client, XMLTV, dig, nslookup, host, ping, telnet
What's broken: Spamassassin (DNSRBL lookups), lynx, yum, fetchmail

This is what I've checked so far:

/etc/host.conf is unchanged from the upgrade ("order hosts,bind")
/etc/resolv.conf is also unchanged from the upgrade:

raven:/etc # cat /etc/resolv.conf
domain chaos.local
nameserver 192.168.1.1
nameserver 192.168.1.5

192.168.1.1 is the server's own address.  As a test, I commented it out, 
forcing it to use 192.168.1.5.  This had no effect on the problem.

Thinking I might have a corrupt library file, I did an 'rpm -q -V' for 
all the glibc packages.  It found no problems.
I also tried different kernels (FC5's  original 2.6.15 kernel, FC5's 
upgraded 2.6.16 kernel, plus an unpatched, self-compiled 2.6.16.2 
kernel), none of which had any effect on the problem.
I downloaded the source for fetchmail, and found the system call it's 
failing on is getaddrinfo(), however, I wrote a little program to use 
getaddrinfo() to resolve the same host that fetchmail failed on, and it 
worked just fine!

I'm at a loss as to what the problem is or even what else to check.  
Anybody got any ideas?

Thanks,

- Cedric