[ale] Fedora 13 DNS weirdness

[Joe Knapka]

I've already ditched F13 and am installing Slackware on my old Dell D600 
laptop, but I wanted to find out if anyone can explain the following 
totally psychotic behavior I experienced under F13:

I set up the laptop's wifi connection on my home network using Network 
Manager (gag,spit) and everything worked fine (?!?).

I went to my SO's house, configured the wifi connection for her network, 
and it connected with no problem.  I could ping the router and the 
upstream gateway by IP or by name.  I could ping things out in the world 
by name:

   jk at jaklaptop:> ping google.com
<successful ping responses from an actual Google IP>

However, other applications that I tried (FireFox, telnet, ssh) did this 
(or in FF's case gave me the equivalent "I can't do that" page):

   jk at jaklaptop:> telnet google.com 80
   Host google.com not found - Name or service unknown.

Weirdly, dig and nslookup had no problem resolving google.com (or any 
other name). But any app that I actually wanted to USE for any practical 
purpose complained about name lookup errors, as in the telnet example above.

I checked everything in Network Manager and the two networks were 
configured identically. I looked at /etc/resolv.conf, /etc/host.conf, 
/etc/nsswitch.conf and everything looked totally OK -- the machine was 
using the correct router and DNS server for my SO's network. I ran 
tcpdump on UDP port 53 while doing a ping and a telnet, and I saw 
successful DNS requests for google.com in both cases.... but telnet 
still complained about "Name or service unknown". I thought maybe it was 
something to do with SELinux, so I disabled that, but no joy.

Then when I got home the laptop connected to my home network and 
everything worked fine again.

I am still at the "WTF?" stage and am not really progressing... hence 
the switch to Slackware.  Any ideas what might have been happening here?

Thanks,

-- JK