xforward(local)

NAME
xforward - provide user-level X forwarding service

SYNOPSIS
xforward [options]

OVERVIEW
xforward provides a user-level X11 forwarding service which can be useful if there are IP network topologies which provide non-transitive routing (e.g. routers which implement policy packet screening).

OPTIONS

-display display

    Specifies the destination display where the user wants applications to appear. Without this argument, xforward will use the DISPLAY environment variable.

-allow allowed-host1 [allowed-host2 ... allowed-host16]

    Only connections from allowed-hosts are permitted. At least one allowed-host must be specified, and at most sixteen are allowed.

DESCRIPTION

xforward will choose an unused port for the local display, and listen for connections on the local host at that port. xforward informs the user which port to use as the local display, when xforward is first invoked. When it receives a connection, it will create a confirmation pop-up on the destination. If the user confirms the connection request, it will create a separate socket and connect it to the destination, and then commence data piping between the two connections. xforward can handle multiple simultaneous connections.

If there is no activity on a connection for 90 minutes, the connection is closed. If the X server at the destination does not have access control enabled, then xforward will report an error.

If a connection is closed by either end, any buffered data is drained to its destination before xforward will close the corresponding socket on the other end.

SEE ALSO
socket(2), connect(2), listen(2), accept(2), bind(2), select(2)

BUGS
Out-of-band data is ignored/thrown away.

If the initial connection to the destination fails for some reason, the client who connected to the local-display will get an open and immediately closed TCP connection, which may cause indigestion to some programs which expect some sort of server response or an error code indicating failure to connect.

AUTHORS
John Kohl, MIT Project Athena and Digital Equipment Corporation
Modifications for X by Win Treese and Alec Wolman, Digital Equipment Corporation

DISTRIBUTION
The file NOTICE in the xforward distribution specifies the terms for distributing xforward. The current version of xforward can be found by anonymous FTP from crl.dec.com:/pub/DEC/xforward.tar.Z.