Telnet send-location option
A Telnet option for sending a user's location to the server.
Killian, E., "Telnet send-location option", RFC 779, DOI 10.17487/RFC0779, April 1981, <https://www.rfc-editor.org/info/rfc779>.
@misc{rfc779,
series = {Request for Comments},
number = 779,
howpublished = {RFC 779},
publisher = {RFC Editor},
doi = {10.17487/RFC0779},
url = {https://www.rfc-editor.org/info/rfc779},
author = {E. Killian},
title = {{Telnet send-location option}},
pagetotal = 2,
year = 1981,
month = apr,
} RFC text
Network Working Group E. Killian
Request for Comments: 779 LLL
April 1981
TELNET SEND-LOCATION Option
1. Command name and code.
SEND-LOCATION 23
2. Command meanings.
IAC WILL SEND-LOCATION
The sender REQUESTS or AGREES to use the SEND-LOCATION option to
send the user's location.
IAC WON'T SEND-LOCATION
The sender REFUSES to use the SEND-LOCATION option.
IAC DO SEND-LOCATION
The sender REQUESTS that, or AGREES to have, the other side use
SEND-LOCATION commands send the user's location.
IAC DON'T SEND-LOCATION
The sender DEMANDS the other side not use the SEND-LOCATION
option.
IAC SB SEND-LOCATION <location> IAC SE
The sender specifies the user's location to the other side via a
SEND-LOCATION subnegotiation. <location> is a sequence of ASCII
printable characters; it is terminated by the IAC SE.
3. Default.
WON'T SEND-LOCATION
DON'T SEND-LOCATION
TELNET SEND-LOCATION Option
4. Motivation for the option.
Many network sites now provide a listing of the users currently
logged in giving their names and locations (see the NAME/FINGER
protocol, RFC 742). The location is useful for physically locating
the user if he or she is nearby, or for calling them (a nearby phone
number is often included). However, for users logged in via the
network, the location printed is often no more than the originating
site name. This TELNET option allows the user's TELNET program to
send the user's location to the server TELNET so that it can be
displayed in addition to the site name. This functionality is
already present in the SUPDUP protocol (RFC 734).
5. Description of the option.
When the user TELNET program knows the user's location, it should
offer to transmit this information to the server TELNET by sending
IAC WILL SEND-LOCATION. If the server's system is able to make use
of this information (as can the ITS sites), then the server will
reply with IAC DO SEND-LOCATION. The user TELNET is then free to
send the location in a subnegotiation at any time.
ISO Plain Language
On this page
§1Why Send a Location
Some sites list people who are logged in, with their names and locations. For a user connected through the network, the location may identify only the site they came from.
The option lets the user's Telnet program provide the user's location so the server can display it alongside the site name. The RFC notes that SUPDUP already has this function.
A network login may identify the connecting site but not where the user is. This option can provide that extra location detail.
§2The SEND-LOCATION Commands
The option name is SEND-LOCATION and its code is 23. IAC WILL requests or agrees to send the location; IAC DO requests or agrees that the other side send it. The WON'T and DON'T forms refuse or prohibit its use.
The default is WON'T SEND-LOCATION and DON'T SEND-LOCATION, so location data is not sent unless the option is negotiated.
The Telnet sides first agree whether to use the option. Until they do, the location is not sent.
§3Sending the Location
The location is sent in a subnegotiation: IAC SB SEND-LOCATION <location> IAC SE. The location is a sequence of printable ASCII characters and ends with IAC SE.
When the user Telnet knows the location, it should offer to send it with IAC WILL SEND-LOCATION. A server able to use the information answers IAC DO SEND-LOCATION; the user Telnet may then send it at any time.
After the server agrees, the user side can send the location as readable text inside a Telnet subnegotiation.