.uucp
Encyclopedia
The name uucp was a pseudo-domain-style suffix used in the 1980s when identifying a hostname not connected directly to the Internet
, but possibly reachable through other inter-network gateways. The suffix was appended to a UUCP
bang path separated with a dot, e.g., host1!host2!host3.uucp.
The suffix prevented messages from being routed via the Simple Mail Transfer Protocol
(SMTP) in mail exchangers, and it indicated that the hostname preceding it was reachable by UUCP
networking. It was not a top-level domain
in the Domain Name System
(DNS) root.
As UUCP hosts were not always uniquely named, and there was no official global table listing them, although 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.
Internet
The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...
, but possibly reachable through other inter-network gateways. The suffix was appended to a UUCP
UUCP
UUCP is an abbreviation for Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. Specifically, a command named uucp is one of the programs in the suite; it...
bang path separated with a dot, e.g., host1!host2!host3.uucp.
The suffix prevented messages from being routed via the Simple Mail Transfer Protocol
Simple Mail Transfer Protocol
Simple Mail Transfer Protocol is an Internet standard for electronic mail transmission across Internet Protocol networks. SMTP was first defined by RFC 821 , and last updated by RFC 5321 which includes the extended SMTP additions, and is the protocol in widespread use today...
(SMTP) in mail exchangers, and it indicated that the hostname preceding it was reachable by UUCP
UUCP
UUCP is an abbreviation for Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers. Specifically, a command named uucp is one of the programs in the suite; it...
networking. It was not a top-level domain
Top-level domain
A top-level domain is one of the domains at the highest level in the hierarchical Domain Name System of the Internet. The top-level domain names are installed in the root zone of the name space. For all domains in lower levels, it is the last part of the domain name, that is, the last label of a...
in the Domain Name System
Domain name system
The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
(DNS) root.
As UUCP hosts were not always uniquely named, and there was no official global table listing them, although 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.