Open Sound System
OSS 4.x User's Guide

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osspartysh - reverse "telnet" utility for OSs technical support


osspartysh -d -p <port> (by the support engineer) osspartysh -h <support_host> -p <support_port> (by the customer)

The osspartysh is an utility that makes it possible to a remote suport engineer to share the session with a customer. The session runs in customer's computer but both the customer and the support engineer can type comands and see the output. It is possible to run commands like vi to edit files.

There is limited chat mechanism based on the comments of the shell (bash) command language. Both peers can send messages by typing the comment character (#) in the beginning of the line.


The osspartysh sessions are established in reverse way when compared to usual remote terminal programs like ssh or telnet. This gives improved security for both sides. The actual internet connection is not crypted so it cannot be used for editing confidential files, etc. However there is no need to send passwords over internet since the protocol doesn't rely on them.


There is no need to open any incoming TCP ports in the firewall or NAT. In addition there is no need to reset any passwords to give the support engineer an access to the system. In addition the customer can see whatever commands are typed and there is good time to hit ^C or ^Z to abort the commands.

Connections opened to the remote terminal server are verified to ensure that using wrong port number doesn't feed invalid commands to the local shell. Otherwise it would be possible that connecting to a wrong port (say http server) sends bad strings to the command interpreter (bash).


The system used as the support terminal needs to have the TCP port opened in the firewall and NAT settings. However this doesn't cause any security risks. If a possible attacker manages to connect to this port then all he can do is sending characters that are (only) shown on the terminal screen.


-dLaunch the utility in terminal server mode (by default connect to a remote terminal.
-h <host>
Give the IP address or host name of the remote terminal server.
-p <port>
Give the TCP port to use. Must be the same in both sides.


o Sometimes it's necessary to hit ^L after running vi or some other curses based program. Without this the keyboard will be locked and
typed characters will not be shown on the screen
o When the session is ended (by typing ^D or exit) the terminal (support) side will be hanging until enter is hit twice. After this the
terminal server will be ready for a new connection by any client. It is
also possible to stop the terminal server by hitting ^C.


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