The telnet command, the rlogin command, and the nop service provide support for the adapter host. This section discusses these utilities.
Note: The following information repeatedly refers to an environment buffer. The adapter stores information in this environment buffer.
The telnet command negotiates the window size (NAWS option, RFC-1073) of the remote user. If the remote accepts the NAWS option, it sends NAWS suboptions when the user's window size changes. When the adapter receives NAWS suboptions, it stores the last received value in the environment buffer.
The telnet command also negotiates the terminal type (RFC-1091, TTYPE option) of the remote user. If the remote agrees to send terminal types, the adapter sends TTYPE SEND suboptions until it finds a case-insensitive match in the terminal database or until the remote has sent all of its types. When the adapter finds a match, it saves that terminal type.
If the remote host sends ANSI , and ansi is in the database, the adapter forms a match and saves ansi (not ANSI ) as the terminal type. If the remote sends all of its types (last type sent twice) and the adapter finds no match, the adapter asks for the type again. The remote starts over, sending its first type (its preferred type), which the adapter saves.
Additionally, the telnet command negotiates the X display location (RFC-1096, XDISPLOC option) of the remote user. If the remote agrees to send the X display location, the adapter sends the XDISPLOC SEND suboption and stores the response in the channel environment buffer.
Finally, the telnet command negotiates the terminal speed (RFC-1079, TSPEED option) of the remote user. If the remote agrees to send the terminal speed, the adapter sends the TSPEED SEND suboption and stores the response in the channel's environment buffer. The response contains the comma-separated input and output speeds.
The first speed is stored as the output speed and the second as the input speed. The telnet command sends the XON and XANY suboptions if the remote accepts the toggle remote flow control option (RFC-1372, TOGGLEFC option). Previously, the telnet command would only send the ON and OFF suboptions (RFC-1080).
The /usr/sbin/getty_hty command passes the preceding user and host information to the /bin/login command when using the telnet command. Sample source code for the getty_hty command resides in the /usr/samples/ntx directory. Do not issue the getty_hty command from the command line. Refer to the "Enabling the getty_hty Command" for procedural details on how to use this command.
When the adapter receives window size commands, it stores the last received value in the environment buffer.
When the adapter receives the last environment string (the terminal information), it sends an AE_ENVIRO event to the device driver if the host set the ENV_EVENT flag.
The /usr/sbin/getty_hty command allows automatic login when using the rlogin command. Sample source code for the getty_hty command resides in the /usr/samples/ntx directory. Do not issue the getty_hty command from the command line. Refer to "Enabling the getty_hty Command" for procedural details on how to use this command.
The nop service is transparent and has no extra protocol associated with it. Therefore, the adapter cannot obtain any remote user environment information.