RFC 927 (rfc927) - Page 3 of 4

TACACS user identification Telnet option

RFC 927                                                    December 1984
TUID Telnet Option


6. Examples

   There are two possible negotiations that result in the double login
   avoidance authentication of a user.  Both the server and the user
   TELNET support the TUID option.

      S = Server, U = User

      Case 1:

         S-> IAC DO TUID
         U-> IAC WILL TUID
         U-> IAC SB TUID  IAC SE

      Case 2:

         U-> IAC WILL TUID
         S-> IAC DO TUID
         U-> IAC SB TUID  IAC SE

   There are also two possible negoitiations that do not result in the
   authentication of a user.  In the first example the server supports
   TUID and the user TELNET doesn't.  In the second example the user
   TELNET supports TUID but the server TELNET doesn't.

      S = Server, U = User

      Case 3:

         S-> IAC DO TUID
         U-> IAC WONT TUID

      Case 4:

         U-> IAC WILL TUID
         S-> IAC DONT TUID

   The TUID is transmitted with the subnegotiation command.  For
   example, if the UUID had the value 1 the following string of octets
   would be transmitted:

      IAC SB TUID 0 0 0 1 IAC SE

   If the UUID had the value 255 the following string of octets would be
   transmitted:

      IAC SB TUID 0 0 0 IAC IAC IAC SE


Anderson