Weird connectivity problem

[Bruno Wolff III]

On Wed, May 13, 2009 at 10:58:16 +0700,
  Old Crankbuster <crankbuster at gmail.com> wrote:
> Hi all, I'm getting something strange that I haven't been able to track
> down yet:
> 
> I can connect fine to the web with eth0 on my laptop, and also through
> wlan0 - problem is that on Fedora i can't use any links out of Google -
> or any other site, for that matter.
> 
> Firefox has cookies turned on, I disabled firewall, and disabled
> SELinux, all to no avail.  Also, cannot update any web based repo's for
> package updates/installs, etc.
> 
> I've also tried various settings for MTU for both interfaces.
> 
> Hmm.  for the moment, I'm clueless...

I suggest checking that dns lookups are working next.