RFC 1572 (rfc1572) - Page 3 of 7
Telnet Environment Option
Alternative Format: Original Text Document
RFC 1572 Telnet Environment Option January 1994
IAC SB NEW-ENVIRON INFO type ... [ VALUE ... ] [ type ... [ VALUE ...
] [ ... ] ] IAC SE
The sender of this command is sending information about
environment variables that have changed. It is identical to the
IS command, except that the command is INFO instead of IS. Only
the side that is WILL NEW-ENVIRON may send an INFO command. The
INFO command is not to be used to send initial information; the
SEND/IS sequence is to be used for that. The INFO command is to
be used to propagate changes in environment variables, and may be
spontaneously generated.
3. Default Specification
The default specification for this option is
WONT NEW-ENVIRON
DONT NEW-ENVIRON
meaning there will not be any exchange of environment information.
4. Motivation
Many operating systems have startup information and environment
variables that contain information that should be propagated to
remote machines when Telnet connections are established. Rather than
create a new Telnet option each time someone comes up with some new
information that they need propagated through a Telnet session, but
that the Telnet session itself doesn't really need to know about,
this generic information option can be used.
5. Well Known Variables
USER This variable is used to transmit the user or account
name that the client wishes to log into on the remote
system. The format of the value the USER variable is
system dependent, as determined by the remote system.
JOB This variable is used to transmit the job ID that the
client wishes to use when logging into the remote system.
The format of the value the JOB variable is system
dependent, as determined by the remote system.
ACCT This variable is used to transmit the account ID that the
client wishes to use when logging into the remote system.
The format of the value the ACCT variable is system
dependent, as determined by the remote system.
Telnet Working Group