Unix & Linux Stack Exchange is a question and answer site for users of Linux, FreeBSD and other Un*x-like operating systems. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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?


share|improve this question
Do you need a username and password for the proxy? Does the password have strange characters? I got problem with '!' and eventually changed my password. – phunehehe Mar 31 '11 at 7:05
No, there is no username or password with the proxy. – Farhat Mar 31 '11 at 10:56

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.

share|improve this answer

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.

share|improve this answer

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.

share|improve this answer
Faulty DNS will normally affect everything, I think it's much more likely a firewall and proxy issue. – penguin359 Apr 1 '11 at 9:22

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.