ssh tunnel fails to connect

[Karl Auer]

On Thu, 2015-07-09 at 00:24 +0200, robert rottermann wrote:
> I need the tunnel for a debugging session. The debugging IDE is running on the 
> local box, the debugee runs on  the remote computer (a raspberry)
> I used telnet only to demonstrate the behaviour.

The fundamental question is: Is anything listening on port 50005 on your
local box? Since you didn't see "connection refused" I'm guessing the
answer is "yes". But you can check with "netstat -an | grep 50005".

If something is listening, is it listening on TCP/50005 or UDP/50005?
Telnet, which you are using to test the tunnel, uses TCP, but your
debuggee might be talking UDP. Again, I'd have half-expected "connection
refused", but worth checking. The above netstat command will tell you.

What protocol is the debuggee speaking? How long is the delay between
"Connected to localhost" and "Connection closed"?

Jeff suggested changing things for telnet - that's a good idea. It might
not solve your problem directly, but it would confirm that the ssh
reverse tunnel was working. You could do this with any service you have
running on your local box - even ssh itself :-)

Regards, K.


-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Karl Auer (kauer at biplane.com.au)
http://www.biplane.com.au/kauer
http://twitter.com/kauer389

GPG fingerprint: 3C41 82BE A9E7 99A1 B931 5AE7 7638 0147 2C3C 2AC4
Old fingerprint: EC67 61E2 C2F6 EB55 884B E129 072B 0AF0 72AA 9882