[Thinlinc-technical] sshd error msg

Peter Åstrand astrand at cendio.se
Tue Jan 18 11:14:05 CET 2011

On Tue, 18 Jan 2011, Peter Åstrand wrote:

> Port 4915 is the tunnel for the PulseAudio sound server, for session 1.
> The ThinLinc client instructs SSHD to create a remote tunnel, so that
> applications in the ThinLinc session can connect to localhost:4915, which
> is forwarded to the client sound server.
> I'm not sure how I should interpret the SSHD logs, the output does not
> match the output of my SSHD. I wonder if this is a bug in SSHD or
> something like that.

I've done some testing on a Ubuntu 10.04 machine. I've also noticed that 
connections to the sound tunnel happens every 2 seconds or so. There are 
two processes responsible for this:


This is probably normal behaviour.

The SSHD messages about "port 0" are confusing, but also "normal". I get 
them as well on Ubuntu 10.04, but the sound works anyway.

I've also managed to reproduce the "connect failed: Connection refused" 
error. It happens if you have requested Sound redirection in the client, 
but the client side sound server (PulseAudio) is not running. I can 
reproduce this problem by killing it manually.

Probably, you get this error because PulseAudio on the client side fails 
or crashes. You should be able to see this in tlclient.log.

We have a known issue with the PulseAudio included with our client: It 
fails on system with the Alsa PulseAudio plugin. On Fedora, you can work 
around the problem by uninstalling the package alsa-plugins-pulseaudio. On 
Ubuntu 9.04, you must instead change the configuration. For example, you 
can rename /usr/share/alsa/pulse-alsa.conf. We haven't verified if this 
also works on 10.04.

This problem will be fixed in the next release.

If you don't need sound, you can also just clear the Sound checkbox in the 
client GUI. That should get rid of these messages.

Best regards, 
Peter Åstrand		ThinLinc Chief Developer
Cendio AB		http://www.cendio.com
Wallenbergs gata 4
583 30 Linköping	Phone: +46-13-21 46 00

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