Firstly, may I know what is your ultimate aim? :-)
I tried the above but now when i try to ping www.google.com ping: unknown host www.google.com is what i get.
Make sure there is a DNS server that is reachable from your machine. The best way would be to run BIND as a caching DNS server ('# service bind start' for Red Hat systems) on the machine running the proxy server, and configure your machine to use this as the primary DNS (use /etc/resolv.conf).
To confirm that this actually works do: $ nslookup gnu.org on your own machine.
[ If you can not have a DNS then try: $ ping 199.232.41.10 If this fails, then read on.]
Next, make sure you have a gateway that actually forwards the packet from your subnet to the outside world. I have had experience using a 'gateway' which never forwarded anything, so make sure that the sysadmin is not lying and the gateway is actually forwarding the traffic.
Checking this is a bit dicey, and depends if there is any firewall that is blocking traffic bound to specific ports and so on. Here are a few things you can try: 1. $ ping google.com 2. Try using an email client like Mutt, Thunderbird, KMail and see if you can send and receive mail or not. If the SMTP and/or POP3 traffic is blocked this would not work. 3. Disable the proxy in the Web browser (eg., Firefox), and try to visit any site. Again if port 80 or 443 traffic is being blocked or not forwarded, this would not work. 4. Try using Gaim. Do not set any proxy, and try to log into Yahoo!, Jabber, or IRC. 5. Try SSH, without using any HTTP proxy tunnelling tool (like Corkscrew). If you have not heard about tunnelling, then most likely you do not have a any such tool. Just do something like: $ ssh foo@external.server
Knowing your ultimate aim would have been helpful.
Regards, Debarshi