linux Internet connectivity

Dear Friend’s,

I have configure ed proxy server. and through x-window I can get connected to internet also
I am getting the ip address from isp and if from terminal window if i will ping to any other www that is yahoo.com or khoj.com
it is pinging. and every thing works ok.

now if I will connect to internet through a script (not through x-window) i am getting ip from isp but if i will try to ping to www that is yahoo.com or khoj.com it is not pinging.

Pl. help me..

regards

D.V.Bhagwat