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Old 04-29-2008, 06:01 PM
jjh jjh is offline
VanDyke Customer Support
Join Date: Feb 2004
Posts: 819
Hi Karebac.

You don't have to configure VShell in any special way for it
to allow your port forward to work.

When you set up port forwarding in your SecureCRT session
and you connect to that session, your local machine starts
listening on your forwarded port (in this case, you are
listening on port 3906 on every IP address in the 127.x.x.x

Any traffic that gets sent to your local port 3906, gets
forwarded through the secure tunnel on port 22 that was set
up when you connected your session. When it reaches the
VShell server, it gets forwarded to port 3906 of your SQL
server machine. If VShell is running on the same machine as
your SQL server, it doesn't go any further. If the SQL
server is running on a different machine, VShell forwards
the traffic along to port 3906 of the SQL machine.

In order to take advantage of the port forward, you must
configure your SQL client to connect to the IP address (or any other IP address in the 127.x.x.x range)
on port 3906. Normally, without using port forwarding, you
connect directly to the IP address of your SQL server.

One common way to check connectivity between an SSH client
and and SSH server is to open a Windows command prompt and
issue the following command from the client machine:

telnet <IP address of the SSH2 server> 22

If the SSH2 server's IP address is, then the
command would be:

telnet 22

If you have connectivity between the two machines on port
22, you should expect to see the version string of the SSH2
server that is listening on port 22.

You might be able to use a similar method to see if your
port forward is configured correctly and working. First try
the following:

Log on to the SQL machine, open a command prompt and issue
the following command:

telnet localhost 3906

If you see a version string or some response that comes from
teh SQL server, you can try issuing the same command from
the SecureCRT machine. You should see the same response
from the SQL server if the port forward is working the way
you want it to.

I know that an SSH2 server is supposed to reply with a
version string, but I don't know what to expect from an SQL
server from that kind of command, so the test might not work
the same way.

You can also open a Windows command prompt on the SecureCRT
machine and issue the following command to find out if it is
truly listening on your localhost IP address on port 3906

netstat -an

Does that show that your machine is listening on port 3906?

Finally, you should also be able to see if your SQL client
is trying to use your port forward by looking at the Vshell
log file. You might need to enable Debug logging to get the
best information. If you would like us to take a look at
your VShell log file, please feel free to send it to us at as it may contain information that you
might not want to post to a public forum.


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