# What is Tor Browser and how does it work?

### About Tor Browser

Tor Browser is based on Mozilla Firefox ESR (Extended Support Release) but has been heavily modified for use with the Tor network. These modifications include additional patches and features that enhance privacy and security, making Tor Browser fundamentally different from Firefox or any other browser.

It is specifically developed to resist online tracking and browser fingerprinting, helping to prevent websites from identifying you based on your browser configuration. While it is technically possible to route other browsers through Tor, doing so exposes you to serious risks of deanonymization and information leakage. For this reason, we strongly discourage using Tor with any browser other than Tor Browser.

By default, Tor Browser does not keep any browsing history. Cookies are only valid for a single session (until Tor Browser is exited or a New Identity is requested). Learn more about the design of Tor Browser.

### The Tor network

Using the Tor network has three main properties:

- Your internet service provider, and anyone watching your connection locally, will not be able to track your internet activity, including the names and addresses of the websites you visit.
- The operators of the websites and services that you use, and anyone watching them, will see a connection coming from the Tor network instead of your real Internet (IP) address, and will not know who you are unless you explicitly identify yourself.
- Tor allows you to circumvent censorship by enabling access to websites and online services that may be restricted or blocked in your region.

### How Tor works

Tor is a network of virtual tunnels that allows you to improve your privacy and security on the Internet. Tor works by sending your traffic through three random servers (also known as relays) in the Tor network. The last relay in the circuit (the "exit relay") then sends the traffic out onto the public Internet. The image below illustrates a user browsing a website over Tor where the traffic goes over multiple hops or relays, represented by the slices of onion, and is encrypted and decrypted at each hop.