Need help: VNCviewer exits on startup when tunneled via SSH

Markus Wollny Markus.Wollny "at" computec.de
Fri, 24 Aug 2001 16:21:41 +0000


Hello!

I'm using VNC to access a linux-box from my Win2k-workstation. I got it
to work so far - alas not quite satisfactorily for my needs.
I'm using SuSE 7.0 on the linux box and OpenSSH for SSH on port 22. The
linux-box and the workstation have got internal IPs in our LAN as well
as external IPs (via NAT). What I need to do is set up VNC as well as
SSH Secure File Transfer to the box to the external IP.

In a first step I just used the OpenSSH distribution that came with SuSE
7.0 - everything was running fine except Secure File Transfer, which
couldn't work because that version of OpenSSH didn't feature it. As the
SuSE 7.0 OpenSSH Distribution was suffering from a securitity flaw
anyway, I got the latest RPM from SuSE (OpenSSH 2.9p1-17) and installed.
sFTP was running flawlessly now, but VNC behaved strangely now.

Before upgrading, I set port-forwarding as follows:
ssh -C -L 5901:localhost:5901 -l myusername external-ip.of.linux.box
I logged myself in with my password and started the vncserver on the
linux-box with
vncserver -localhost :1
Then I startet vncviewer on my workstation using
vncviewer localhost:1
It worked fine. So I didn't change anything about that, not even after
the upgrade.

Then I upgraded to OpenSSH 2.9p1-17. SFTP was now working. Afterwards I
followed the very same steps - started up the tunnel, then the server
and then tried to invoke vncviewer - but when I call it, it just exits
without any error-message whatsoever.

When calling up a wrong IP or a wrong port intentionally when starting
vncviewer, I do get the standard error-message "Failed to connect to
server". As I don't even get this message, I conclude that there is a
tunnel alright. Still, doesn't help... It must have something to do with
the upgrade to OpenSSH 2.9p1-17, as it was running fine before with the
very same configuration.

Does anybody have a clue as to what I am doing wrong? I'd be very much
obliged if anybody could help me with this one. I find VNC so very
useful that I'd really hate considering working with the command-line
only again...

Tanks a lot,

		Markus

This is my sshd_config:
Port 22
Protocol 2,1
ListenAddress 0.0.0.0
HostKey /etc/ssh/ssh_host_key
HostKey /etc/ssh/ssh_host_dsa_key
ServerKeyBits 768
LoginGraceTime 600
KeyRegenerationInterval 3600
AllowTcpForwarding yes
GatewayPorts yes
PermitRootLogin yes
IgnoreRhosts yes
StrictModes yes
X11Forwarding yes
X11DisplayOffset 10
PrintMotd yes
KeepAlive yes
SyslogFacility AUTH
LogLevel INFO
RhostsAuthentication no
RhostsRSAAuthentication no
HostbasedAuthentication no
RSAAuthentication yes
PasswordAuthentication yes
PermitEmptyPasswords no
ChallengeResponseAuthentication no
Subsystem	sftp	/usr/lib/ssh/sftp-server
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