Cannot access network on the command line in Ubuntu 10.04

Question

I am having an issue which I am unable to diagnose. I am unable to access outside the local network from the command line. Strangely, ftp works from the command line. But ping, links, traceroute, wget or other utilities are unable to connect. The network works fine from graphical browsers like firefox. We have a network proxy at the workplace which I set using environment variables http_proxy and so on. Any ideas on how could I diagnose this?

Thanks.

Answer 1

It's possible that DNS isn't configured correctly. You didn't give us example error messages from ping, traceroute, etc, or the value of the "http_proxy" environment variable. If "http_proxy" just contains an IP address, and you're doing "ping some_fqdn", then it's entirely possible that /etc/resolv.conf doesn't have the correct contents in it, or that /etc/nsswitch.conf isn't correct.

Answer 2

If your proxy is not blocking the other access you need, you may have to configure the proxy for all apps/services, not only for ftp and browsers. For example, for apt you need to do:

nano /etc/apt/apt.conf

Acquire::http::Proxy "http://proxy_hostname_or_ip:port/";

or for authenticated access:

Acquire::http::Proxy "http://user:passwd@proxy_hostname_or_ip:port/";

You probably have a way to configure the proxy for everything in your config or system menu.

Answer 3

It sounds to me like there is a firewall in place blocking access to the outside world and the proxy server handles the required access to FTP and the web.