Hi,

I want client X to be able to connect with this command: ssh -L 30300:localhost:8080 -R 1037:localhost:55555
Client Y to be able to connect with: ssh -L 30300:localhost:8080 -R
1038:localhost:55555
and so on
but client Y should be forbidden to connect with: ssh -L
30300:localhost:8080 -R 1037:localhost:55555

If client X has remote port 1037 on the server then client Y should be
forbidden to do remote port-forwarding on port 1037 if client X is not
connected.

Can't it be restricted somehow with some Linux commands, or openssh configuration?

I mean restrict only client X (which is behind a certain ip address)
to listen to port 1037 on the server.

I'm not Linux user, and have minimal knowledge about Linux, but maybe
someone knows...

Thank you,
Adriana

No, SSH doesn't provide that level of flexibility, but you could possibly run two seperate instances of sshd and control which clients are allowed to connect to it in the first place using tcpwrappers.