IETF RFC 2941 PDF

This document describes the authentication option to the telnet [1] protocol as a generic method for negotiating an authentication type and mode including whether encryption should be used and if credentials should be forwarded. While this document summarizes currently utilized commands and types it does not define a specific authentication type. Separate documents are to be published defining each authentication type.

This document updates a previous specification of the telnet authentication option, RFC 1416 [2], so that it can be used to securely enable the telnet encryption option [3].