As per Relevance of the word receiver, we have this rfc below:
NWG/RFC# 727 MRC 26-APR-77 18:24 40025
Telnet Logout
Network Working Group Mark
Request for Comments 727 MIT-
NIC 40025 27 April 1977
TELNET Logout
1. Command name and code
LOGOUT 18
2. Command meanings
IAC WILL
The sender of this command REQUESTS permission to, or
that it will, forcibly log off the user process at its end
IAC WON'T
The sender of this command REFUSES to forcibly log off the
process at its end
IAC DO
The sender of this command REQUESTS that the receiver forcibly
off the user process at the receiver's end, or confirms that
receiver has its permission to do so
IAC DON'T
The sender of this command DEMANDS that the receiver not
log off the user process at the receiver's end
3. Default
WON'T
DON'T
i.e., no forcible logging off of the server's user process
4. Motivation for the option
Often, a runaway user process could be hung in such a state that
cannot be interrupted by normal means. Conversely, the system
could be bottlenecked so that response delays are intolerable.
user (human or otherwise) eventually will time out out of
[page 1]
NWG/RFC# 727 MRC 26-APR-77 18:24 40025
Telnet Logout
and take the drastic means of closing the connection to free
from the hung process. In some situations, even the simple
of logging out can take a long time
Some systems treat a close to mean that it should log out its
process under it. However, many hosts merely "detach" the process
that an accidental close due to a user or temporary hardware
will not cause all work done on that job to be lost; when
connection is re-established, the user may "attach" back to
process. While this protection is often valuable, if the user
giving up completely on the host, it can cause this hung job
continue to load the system
This option allows a process to instruct the server that the
process at the server's end should be forcibly logged out instead
detached. A secondary usage of this option might be for a server
warn of impending auto-logout of its user process due to inactivity
5. Description of the option
When a user decides that it no longer wants its process on the
host and decides that it does not want to wait until the host'
normal log out protocol has been gone through, it sends IAC
LOGOUT. The receiver of the command may respond with IAC
LOGOUT, in which case it will then forcibly log off the user
at its end. If it responds with IAC WON'T LOGOUT, then it
that it has not logged off the user process at its end, and if
connection is broken, the process very possibly will be detached
A truly impatient user that feels that it must break away from
server immediately could even send IAC DO LOGOUT and then close.
the worst, the server would only ignore the request and detach
user process. A server that implements the LOGOUT option should
to log out the user process despite the sudden close and even
inability to confirm the LOGOUT request
6. A sample implementation of the option
The server implements the LOGOUT option both for accepting
requests and for auto-logout warning
Case 1:
The user connects to the server, and starts interacting with
server. For some reason, the user wishes to terminate
with the server, and is reluctant to go through the normal log
procedure, or perhaps the user is unable to go through the
[page 2]
NWG/RFC# 727 MRC 26-APR-77 18:24 40025
Telnet Logout
log out procedure. It does not want the process at the server
more, so it sends IAC DO LOGOUT. The server verifies the
with IAC WILL LOGOUT, and then forcibly logs off the user
(perhaps by using a system call that causes another process to
logged out). It does not have to close the connection unless
user closes or it wants to close. Neither does it wait until
user has received its confirmation--it starts the log
immediately so if the user has in the mean time closed
connection without waiting for confirmation, its logout
still is performed
Case 2:
The user connects to the server, and after logging in, is idle
a while, long enough to approach the server's autologout time
The server shortly before the autologout sends IAC WILL LOGOUT
the user sees this and sends IAC DON'T LOGOUT, and continues
on the host. Nothing prevents the server from logging out
user process if inactivity continues; this can be used to
a malicious user from locking up a process on the server host
the simple expedient of sending IAC DON'T LOGOUT every time
sees IAC WILL LOGOUT but doing nothing else
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
RFC documents can be found at I.E.T.F.
Relevance System Copyright © 2002 Spectrum WorldResearch
other technical nosh by ServerMasters Corporation
collaboration of BobX
