[ale] Fedora 13 DNS weirdness

[Brian Pitts]

On 08/08/2010 11:05 PM, Joe Knapka wrote:
> 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.

I might try

strace -v -e trace=network telnet google.com 80

to see things from telnet's perspective.

Also, I might try disabling ipv6.

Do the /bin/true thing described below, then reboot.

http://www.cyberciti.biz/faq/redhat-centos-disable-ipv6-networking/

-- 
All the best,
Brian Pitts