Get Proxy settings when you don't have access to see them

Open a command prompt and enter the following command

Command Line

netsh winhttp import proxy source = ie

You should get output like:

Current WinHTTP proxy settings:

    Proxy Server(s) :  some.corp-proxy:8080

    Bypass List     :  some.corp-servers...

Chrome

If you have Chrome it has an interesting feature for doing so as well.

chrome://net-internals/#proxy

This will give some results similar to the following

Proxy server: some.corp-proxy:8080
Bypass list: 
  some.corp-server...