Subject: bin/15340: ssh X11 forwarding is broken
To: None <>
From: Matthias Scheler <>
List: netbsd-bugs
Date: 01/23/2002 10:58:53
>Number:         15340
>Category:       bin
>Synopsis:       ssh X11 forwarding is broken
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Jan 23 01:59:00 PST 2002
>Release:        NetBSD 1.5ZA (2002-01-23), NetBSD 1.5.3_ALPHA (2001-10-01)
Matthias Scheler                        
System: NetBSD 1.5ZA NetBSD 1.5ZA (LYSSA) #0: Tue Jan 22 13:33:11 CET 2002 i386
Architecture: i386
Machine: i386

System: NetBSD 1.5.3_ALPHA NetBSD 1.5.3_ALPHA (COLWYN) #0: Thu Oct 11 21:58:18 CEST 2001 i386
The X11 forwarding in NetBSD's SSH works only between two directly connected
hosts. It doesn't work if you try to use a scenario like this:

A:	Host where X11 server runs
	|	SSH with X11 Forwarding
B:	Internet Gateway
	|	SSH with X11 Forwarding
C:	Host behind Internet Gateway

It is not a problem with the SSH configuration on B and C, X11 forwarding
is enabled there. The failure can even be reproduced if you connect from
a NetBSD box to itself two times nested. The same setup works without any
problem on a Solaris 9 box using the included SSH client.


None provided.