.uucp

Infobox Top level domain
name=.uucp
background=#ADFF2F
introduced=1985
type=Pseudo-domain-style host suffix
status=Formerly used in addresses and site names
registry=UUCP Mapping Project (informally)
sponsor=
intendeduse=To designate an address or hostname connected via UUCP networking
actualuse=Was widely used in late 1980s, but is no longer in use
restrictions=No registrations are possible, as this domain is not in the root
structure=Appended to right of UUCP hostnames; since hostnames are not necessarily globally unique, full "bang path" may be needed to actually identify them
document=
disputepolicy=
website=|

.uucp was a pseudo-domain-style suffix used in the late 1980s when identifying a hostname not connected directly to the Internet but possibly reachable through inter-network gateways. In this case, it indicated that the hostname preceding it was reachable by UUCP networking. This was one of several apparent "top-level domains" that were not actually in the Internet Domain Name System (DNS) root, but were sometimes used in addresses during the time when non-Internet networks remained in wide use.

As UUCP hosts were not always uniquely named, and there was no official global table listing them (though the "UUCP Mapping Project" was an informal effort to create such a list), actual access to one (e.g., for routing e-mail to it) required the use of a full bang path, which did not follow domain-name-style syntax, unless the particular software being used had been programmed to recognize particular hostnames in a domain style and route to them.