.onion

.onion

Introduced	2004
TLD type	Pseudo-domain-style host suffix
Status	Not in root, but used by Tor clients, servers, and proxies
Registry	Tor
Intended use	To designate a hidden service reachable via Tor
Actual use	Used by Tor users for services in which both provider and user is anonymous and difficult to trace
Registration restrictions	Addresses are "registered" automatically by Tor client when a hidden service is set up
Structure	Names are opaque strings such as jv6g2ucbhrjcnwgi.onion, generated from public keys
Documents	Tor design document
Dispute policies	See Tor abuse FAQ
Registry website	www.torproject.org

.onion is a pseudo-top-level domain host suffix (similar in concept to such endings as .bitnet and .uucp used in earlier times) designating an anonymous hidden service reachable via the Tor network. Such addresses are not actual DNS names, and the .onion TLD is not in the Internet DNS root, but with the appropriate proxy software installed, Internet programs such as Web browsers can access sites with .onion addresses by sending the request through the network of Tor servers. The purpose of using such a system is to make both the information provider and the person accessing the information more difficult to trace, whether by one another, by an intermediate network host, or by an outsider.

Addresses in the .onion pseudo-TLD are opaque, non-meaningful strings which are automatically generated based on a public key when a hidden service is configured.

The "onion" name refers to onion routing, the technique used by Tor to achieve a degree of anonymity.

A few examples of .onion hosts can be found in the main Wikipedia article on Tor, under hidden services.

.exit

.exit is a pseudo-top-level domain used by Tor users to indicate on the fly to the Tor software the preferred exit node that should be used while connecting to a service such as a web server, without having to edit the configuration file for Tor (torrc)

The syntax used with this domain is hostname + .exitnode + .exit, so that a user wanting to connect to www.torproject.org through node tor26 would have to type www.torproject.org.tor26.exit in his/her browser as the URL.

Example uses for this include accessing a site available only to addresses of a certain country or checking if a certain node is working.

Users can also type exitnode.exit alone to access the IP address of exitnode

External links

• Tor: Hidden Service Configuration Instructions
• Tor Rendezvous Specification
• Wiki index of .onion resources available only through Tor