Linux Proxy Authentication
 

I've set up my linux OS to use the correct proxy ip. I've entered it into the Network proxy pref, and it used to work untill the network admin made it so you had to authenticate your connection. I have my password and username but where do i enter it. In the Network Proxy pref i've entered my username and password but it also requires me to enter the authentication info in the prefs of the web browser. What can i do to authenticate my connection?