google&yahoo blacklisting my ubuntu box!

This is very strange, I doubt there is actual "blacklisting" going on but well let me explain the situation.

I set up a ubuntu (edgy) install on a machine with a wireless nic.
I set up the networking to use my smothwall box as a gateway (as per smooth walls manual).

The box can now acess most of the internet. I can use the syaptic package manager and use firefox to contact almost any website I desire.

However I can not contact any serach engine (www.google.com, www.yahoo.com or www.alltheweb.com). I get a network time out error. This seems strange but it gets worse.

If I attempt to contact any of these aforementioned addresses from the ubuntu box then the entire home network will loose access to that address for about 12 hours.

If I wait 12 hours the other machines on the network can access the sites again, but as soon as I try it with the Ubuntu box, bam; 12 hours network wide no google or whatever search engine I tried.

this only happens (as far as I can tell) for search engines. any other web site loads up without issue.

any help, pointers or anything appreciated,

-dm