Historical special hostnames

.noconnect

SYNTAX: [string].noconnect

When Tor sees an address in this format, it immediately closes the connection without attaching it to any circuit. This is useful for controllers that want to test whether a given application is indeed using the same instance of Tor that they’re controlling.

This feature was added in Tor 0.1.2.4-alpha, and taken out in Tor 0.2.2.1-alpha over fears that it provided another avenue for detecting Tor users via application-level web tricks.

.onion (version 2)

  SYNTAX:  [digest].onion
           [ignored].[digest].onion

In version 2 .onion addresses, (removed along with the rest of v2 onion services in 0.4.5.11) the “digest” part of the address is the first eighty bits of a SHA-1 digest of the hidden service’s identity key (SHA1(DER(PK))), encoded in base 32.

The “ignored” portion of the address is intended for use in vhosting, and is supported in Tor 0.2.4.10-alpha and later.