jackd1000

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I'm trying to forward a port through an SSH tunnel between two red hat 5.3 hosts.

I assume that I need to the following :-

i) on the 'client' side

ssh -L 15210:destination_host:1521

ii) on the 'server' side I need to do a similar thing , except redirecting the other way

Is this kind of right ? What are the exact arguments to 'ssh'? And what is the difference between running 'ssh -L' and 'ssh -R' ?

Yours in anticipation
Jack

acid_kewpie

the client command seems fine, you need to do nothing at all on the server side.

L does client to server forwarding, R does server to client forwarding

jackd1000

I have now got the client side running fine.
On the server I have a daemon process listening on port 1521 and I want these coming back on 15210, naturally, as that is the port of my client side process.

However if on the 'client' side I run

ssh -R 1521:localhost:15210 user@serverhost

I get a problem as my daemon is already listening on 1521. How do I make sure that my server side port 1521 responses get to my client side 15210 port ?

acid_kewpie

they don't get to that port, I think you're misunderstanding something. When your client connects to 15120 it establishes a fully stateful TCP session with the remote SQL box, just like if you connected directly to it. No return data needs to be sorted at all.

jackd1000

Chris

many thanks for your previous email.

I'm still getting problems.

I am running, on my client machine, a port forwarder interactively :-

**

ssh -v -L 15210:db_server:1521 -N orcl@db_server
oracle@db_server's password:
debug1: Authentication succeeded (password).
debug1: Local connections to LOCALHOST:15210 forwarded to remote address db_server:1521
debug1: Local forwarding listening on 127.0.0.1 port 15210.
debug1: channel 0: new [port listener]
debug1: Local forwarding listening on ::1 port 15210.
debug1: channel 1: new [port listener]
debug1: Entering interactive session.

**

I then try to connect to my db_server from the client machine and I get :-

**

debug1: Connection to port 15210 forwarding to db_server port 1521 requested.
debug1: channel 2: new [direct-tcpip]


**


From what I can tell this is about as far as I can get. My server process I know is not receiving any connection requests.

How do I debug the server side ? What are the likely causes of things not working properly ?


Regs
JAck

acid_kewpie

on the tunnel, specify 127.0.0.1 instead of the external host name. This name is as resolved by the REMOTE machine, so 127.0.0.1 will be the loopback interface on the server.

jackd1000

Chris

You are a genius, it works just fine.

Regs
Jack