Background

The Internet Architecture Board (IAB) issues specifications, and updates to the specifications, in the form of RFCs. RFCs describe protocols (as well as other information) of interest to the Internet community.

The Host Requirements RFCs are a statement of requirements for host system implementations of the Internet protocol suite, when these host systems are connected to the Internet. They do the following:

• Reference other RFCs and documents describing the current specifications for the Internet protocols

• State a set of requirements for each referenced protocol

• Clarify issues where the source document may be confusing

• Correct errors in the referenced documents

• Describe specific provisions overriding the original documents

The Host Requirements RFCs also indicate whether the requirements they discuss are must, must not, should, should not, or may level requirements. If an implementation complies with all must and should level requirements, it is considered unconditionally compliant. If an implementation complies with all must level requirements, but not necessarily all should requirements, it is considered conditionally compliant.

Note: This appendix describes Digital UNIX's conformance to must and must not level requirements only. Although Digital UNIX complies with the vast majority of should, should not, and may level requirements described in the Host Requirements RFCs, compliance with should, should not, and may level requirements is beyond the scope of this appendix.

RFCs are frequently issued or updated. When updates are issued, earlier versions of the RFC are rendered obsolete. The Host Requirements RFCs were issued in October 1989. Where RFCs referenced by the Host Requirements RFCs have been updated since October 1989, the RFC number of the updated version, as well as the number of the version it rendered obsolete, are noted.

The following two RFCs are of general importance to the Internet community because they contain information that has an impact on all implementations of all protocols:

• RFC 1780: Internet Official Protocol Standards

  Describes the state of standardization of protocols used in the Internet. It lists recent changes in protocols, and also indicates a status of required, recommended, elective, limited use, or not recommended for each protocol described. Digital UNIX was validated against RFC 1600. RFC 1600 renders RFCs 1540, 1500, 1410, 1360, 1280, 1250, 1200, 1140, 1130, 1100, and 1083 obsolete.

• RFC 1780: Assigned Numbers

  Lists the assigned values of the parameters used in the various protocols, for example, IP codes, TCP port numbers, TELNET option codes, ARP hardware types, and terminal type names.

  The Host Requirements RFCs reference RFC 1010, an earlier version of this RFC. Digital UNIX was validated against RFC 1340. RFC 1340 renders RFC 1060, 1010, as well as many earlier RFCs, obsolete.