Browse Prior Art Database

An Access Control Protocol, Sometimes Called TACACS (RFC1492)

IP.com Disclosure Number: IPCOM000002320D
Original Publication Date: 1993-Jul-01
Included in the Prior Art Database: 2019-Feb-10
Document File: 21 page(s) / 25K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

C. Finseth: AUTHOR

Related Documents

10.17487/RFC1492: DOI

Abstract

This RFC documents the extended TACACS protocol use by the Cisco Systems terminal servers. This same protocol is used by the University of Minnesota's distributed authentication system. This memo provides information for the Internet community. It does not specify an Internet standard.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group C. Finseth Request for Comments: 1492 University of Minnesota July 1993

An Access Control Protocol, Sometimes Called TACACS

Status of this Memo

This memo provides information for the Internet community. It does not specify an Internet standard. Distribution of this memo is unlimited.

Background

There used to be a network called ARPANET. This network consisted of end nodes (hosts), routing nodes (IMPs) and links. There were (at least) two types of IMPs: those that connected dedicated lines only and those that could accept dial up lines. The latter were called "TIPs."

People being what they were, there was a desire to control who could use the dial up lines. Someone invented a protocol, called "TACACS" (Terminal Access Controller Access Control System?), which allowed a TIP to accept a username and password and send a query to a TACACS authentication server, sometimes called a TACACS daemon or simply TACACSD. This server was normally a program running on a host. The host would determine whether to accept or deny the request and sent a response back. The TIP would then allow access or not, based upon the response.

While TIPs are -- shall we say? -- no longer a major presence on the Internet, terminal servers are. Cisco Systems terminal servers implement an extended version of this TACACS protocol. Thus, the access control decision is delegated to a host. In this way, the process of making the decision is "opened up" and the algorithms and data used to make the decision are under the complete control of whoever is running the TACACS daemon. For example, "anyone with a first name of Joe can only login after 10:00 PM Mon-Fri, unless his last name is Smith or there is a Susan already logged in."

The extensions to the protocol provide for more types of authentication requests and more types of response codes than were in the original specification.

The original TACACS protocol specification does exist. However, due to copyright issues, I was not able to obtain a copy of this document

Finseth [Page 1]

RFC 1492 TACACS July 1993

and this lack of access is the main reason for the writing of this document. This version of the specification was developed with the assistance of Cisco Systems, who has an implementation of the TACACS protocol that is believed to be compatible with the original specification. To be precise, the Cisco Systems implementation supports both the simple (non-extended) and extended versions. It is the simple version that would be compatible with the original.

Please keep in mind that this is an informational RFC and does not specify a standard, and that more information may be uncovered in the future (i.e., the original specification may become available) that could cause parts of this document to be known to be incorrect.

This RFC documents the extended TACACS protocol use by the Cisco Systems terminal servers. This same protocol is used by the University of Minnesota’s distributed authentication system.

1. Pro...

Processing...
Loading...