Firefox internet access detection

[R Kimber]

Bearing in mind that my PC is continually accessing the internet (news,
mail, ntp, boinc, etc), is there a simple app that, when I load a *local*
web page in my browser, would tell me if that page is accessing the internet
and what site it is accessing? I.e. I need to be able to distinguish
between what the browser (Firefox) is doing and what everything else is
doing. I suppose a Firefox add-on would be the answer, but I don't know of
one. Any suggestions?

- Richard.
-- 
Richard Kimber
Political Science Resources
http://www.PoliticsResources.net/