Hi; I cannot get on the Internet using firefox on my Ubuntu workstation, so I thought umm may be they put my IP in a black list? so I use dhclient to get a new IP and it worked but now I cannot get on the Internet again and dhclient does not work, I mean I do get a new IP an I can ping or even download apt-get install etc, BUT cannot get on the Internet? I'd like to know how I can see which ports are being blocked? like port 80? Any info is appreciated. using ubuntu9/debian flavor linux thanks.