What Causes Firefox to Redirect?

Firefox, like other brands of Web browsers, may occasionally redirect a user.

Like any other Web browser, Firefox regularly redirects users to different Web addresses. A Web address is technically known as a Uniform Resource Locator, or URL. The URL contains several different sections; a change in any one of those elements will cause all existing links to the original URL to fail. The World Wide Web has a built-in mechanism to enable website administrators to avoid changed URLs resulting in “dead links" that lead nowhere.

Redirects

A redirect is a specific action where visitors to one URL are automatically diverted to another. There are many different techniques to redirecting traffic from one address to the other, but the basic process involves the Web server informing the Firefox Web browser of a change of address, via a standard set of codes.

Hypertext Transfer Protocol

The Hypertext Transfer Protocol, better known as HTTP, is the message format that all Web browsers and Web servers use to communicate with each other. Each message has a section called “HTTP headers” followed by a message body. The HTTP headers are a series of lines, each containing a parameter and value pair. The HTTP specification includes status codes that are a shorthand for information that a server can use when sending its message to a Web browser like Firefox.

Web Transaction

When Firefox is given an address, wither typed directly into the address field, or populated automatically by clicking on a link, it first finds the IP address for the domain name contained in the address. The Internet Protocol defines the addressing system for the Internet and the Firefox Web browser has to find that address by sending the domain name (the “www.something.xxx”) to a Domain Name System server. Firefox then sends a short message to the server at that address. If the page exists, the server responds with an HTTP message carrying the code of the page in the message body. If the page does not exist, the server's reply has an empty body and one of the HTTP headers contains a 404 code, which means “page not found.” If a redirect is in place for that page, the server's reply will contain one of the redirect codes instead of the 404 code. Those codes are 301 (for a permanent redirect) or 302 (for a temporary redirect).

Firefox Redirects

The receipt of a redirect code causes Firefox to implement the redirect. The message containing the code also contains the new URL that Firefox should go to for the file. If the page is permanently redirected, Firefox will remember the new address and substitute it every time in the future that it is instructed to go to the old address. If the redirect is temporary, Firefox goes to the new address this time only and does not store the new address. The next time it is requested to go to the original address, it will go there.

References

• The World Wide Web Consortium: Status Code Definitions
• SEO Company: URL Redirect
• Web Source: Redirect to a New Page