openssh unix dev - Nov 2003 - Problems with port forwarding on Suse Linux 9.0

Problem: I'm trying to forward a port (say, port 25) of a SuSE 9.0 Linux
system to an external client system (in this case running RedHat 9.0). 
It doesn't work, and the problem seems to be on the SuSE side.

Details
======On the client system, I run (where "suse-server" is the IP
address of my
SuSE server system to which I'm trying to connect)

client> /usr/bin/ssh -f -L 5599:localhost:25 suse-server sleep 100
client> telnet localhost 5599
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
channel 2: open failed: connect failed: Connection refused
Connection closed by foreign host.

This is a problem with the port forwarding.  When I connect to the same
port from the suse-server computer, it works:

suse-server> telnet localhost 25
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 catfish.home ESMTP Postfix


I've pulled my hair out over this one, to no avail, nor have I found
anyone else with the problem.  More details:

client> rpm --query openssh                                             
openssh-3.6.1p2-19
client> rpm --query openssl
openssl-0.9.7a-23

suse-server> rpm --query openssh
openssh-3.7.1p2-18
suse-server> rpm --query openssl
openssl-0.9.7b-74

Thanks,
-- Bob

On Sun, 2003-11-30 at 17:42, Andrew Farmer wrote:
> On Sun, 30 Nov 2003 08:37:51 -0800, Bob Fischer muttered:
> > Problem: I'm trying to forward a port (say, port 25) of a SuSE 9.0
Linux
> > system to an external client system (in this case running RedHat 9.0).
> > It doesn't work, and the problem seems to be on the SuSE side.
> 
> The problem is that only root can bind to "privileged" ports
(<1024).
> You'll have to ssh in as root to create this forwarding.
Good thought, but already I tried it.  Anyway, I get the same problem
with unpriviledged ports.

Here's the log of hte same problem, ssh-ing into the SuSE server as
root:


client> /usr/bin/ssh -f -L 5599:localhost:25 root at suse-server sleep 100
Password:
client> telnet localhost 5599
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
channel 2: open failed: connect failed: Connection refused
Connection closed by foreign host.

-- Bob

It also fails on an even simpler example.  I am logged on as root, and
the ssh client and server are the same machine:

suse-server # /usr/bin/ssh -f -L 5600:localhost:25 localhost sleep 100
Password:
suse-server # telnet localhost 5600
Trying ::1...
channel 3: open failed: connect failed: Connection refused
Connected to localhost.
Escape character is '^]'.
Connection closed by foreign host.

-- Bob

Bob Fischer wrote:
[snip]
> On the client system, I run (where "suse-server" is the IP
address of my
> SuSE server system to which I'm trying to connect)
> 
> client> /usr/bin/ssh -f -L 5599:localhost:25 suse-server sleep 100
> client> telnet localhost 5599
> Trying 127.0.0.1...
> Connected to localhost.
> Escape character is '^]'.
> channel 2: open failed: connect failed: Connection refused
> Connection closed by foreign host.
[snip]
> suse-server> telnet localhost 25
> Trying ::1...
> telnet: connect to address ::1: Connection refused
Try setting the forward to "-L 5599:127.0.0.1:25".  I suspect sshd is
trying to connect to the IPv6 address of "localhost", which is
refused,
and sshd doesn't try the IPv4 address.

-- 
Darren Tucker (dtucker at zip.com.au)
GPG key 8FF4FA69 / D9A3 86E9 7EEE AF4B B2D4  37C9 C982 80C7 8FF4 FA69
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.