Configuring Mozilla Firefox to Use a Proxy Server

Proxy Servers have long been used to masquerade IP addresses on the Internet to protect people’s privacy. They have also been used for some nefarious purposes, such as circumventing a company’s corporate firewall; or even directing hacking attempts through a proxy server to hide the original source of the attack.

If you are connected to the Internet through a router, you are technically behind a hardware proxy server right now. Here’s how a proxy server works:

  1. Your computer passes all of your outbound Internet traffic to your router.
  2. The router, acting as if it were your computer, passes this information out to the Internet.
  3. Information that the router receives back is delivered to your computer.

While behind a router, your computer has no direct access to the outside Internet at all. All communication that your computer does with the Internet is entirely done by proxy.

Because your router and computer are likely in the same location, there isn’t much practical use of this example. The real magic comes in when direct your traffic through a proxy server half a world away.

We’re going to show you how to set up a proxy server within Mozilla Firefox:

  1. Open Mozilla Firefox and click on the ‘Tools’ menu.
  2. Click on the ‘Options…’ menu item to open the Options screen.
  3. Click on the ‘Advanced’ tab at the top of the Options screen.
  4. In the ‘Connection’ pane, click on the ‘Settings…’ button to open the Connection Settings screen.
  5. In the ‘Configure Proxies to Access the Internet’ pane, click on the ‘Manual proxy configuration’ radio button.
  6. In the ‘HTTP Proxy:’ field, enter the address of your proxy server. The address of your proxy server will be in a DNS hostname form such as or it will be in an IP address form such as
  7. In the ‘Port:’ field, enter the port to connect to your proxy server. This will generally be port 80, but some proxy servers assign a custom port such as 8080 to bypass corporate firewalls.
  8. Click the ‘OK’ button on the Connection Settings screen.
  9. Click the ‘OK’ button on the Options screen.
  10. Open a website. Your web browser will connect to the proxy server and attempt to use it to browse Internet. Depending on how your proxy server is set up it may prompt you to enter a username and password.

If you have any problems with getting your proxy server set up, double-check that you entered the address and port of your proxy server correctly.