I am using gnome-classic on Ubuntu 14.04. I am confused about different ways that can set up proxies.
In gnome-classic's Settings->Network->Network Proxy,
(1) When the method is Manual, (See screen shot below)
will the settings of HTTP proxy, HTTPS Proxy, and FTP proxy affect all and only the programs that use HTTP, HTTPS, and FTP respectively?
will the setting of SOCKS proxy with a port affect all and only those programs attached to the port?
(2) when the method is Automatic, it says "Web Proxy AutoDiscover is used when a configurtion URL is not provided" (see screen shot below). But I check that there is no proxy. Do I miss something?
In a program, such as Firefox or ssh client, if I set up a proxy in its settings, will the proxy only affect the program, not any other programs?
In the way of environment variables, what programs are affected by the values of
What are differences and relation between the above three way? For example, are the gnome network settings for proxy essentially the same as those settings in proxy environment variables?
How do the proxy settings in the three ways (in a program, in Gnome network settings, and in environment variables) work together?
Does some setting override another setting?
are the proxy settings all used, in the way that the proxy servers are used in a chain (i.e. the program first uses the proxy server in gnome network setting, which in turn uses the proxy server in the environment variables, which in turn uses the proxy server in the program) ?
are the proxy settings all used, in the way that for a program to use a proxy server, the proxy server must be set up in gnome network settings, in the program's own settings, and/or in an environment variable? For example, do I need to set up a proxy server in my browser after set up the proxy server as HTTP proxy in gnome network settings?