تنظیم پراکسی در اوبونتو

You need to specify this proxies and apply them system wide. Just collect the IP and Ports for your HTTP and HTTPS proxies and do this with the system proxy setting GUI. Search for Network Proxy in dash.

Try user_name:password@Proxy_IP for the authentication. This seems to be the way to configure it in the configuration file. source

Ubuntu Main

Mate IN mate there's a checkbox for this if you click on details