Home / server / Questions / 910526
Accepted
Zama Ques
Asked: 2018-05-04 03:23:57 +0800 CST

SSH Local Port forwarding working from localhost only

  • 772

I can directly access Host A ( 10.100.64.112) from my HomePC but cannot directly access Host B (172.88.3.31) . To access Host B , I need to first ssh to Host A and then to Host B .

To directly access Host B , I tried to set up an SSH tunnel using local port forwarding with the below command on Host A

 Host A # ssh  [email protected] -L 4420:172.88.3.31:22

Now I tried to validate whether the tunnel is working or not

 Host A # ssh 10.100.64.112 -p 4420
 [email protected]'s password:

It works fine and it takes me to Host B

But If I access directly the tunnel from my HOmePC , it does not work

    $  ssh 10.100.64.112 -p 4122
    ssh: connect to host 10.100.64.112 port 4122: Connection refused

On checking with netstat , it shows the following

$ sudo netstat -an | grep 4420
tcp        0      0 127.0.0.1:4420              0.0.0.0:*                   LISTEN
tcp        0      0 ::1:4420                    :::*                        LISTEN

Please suggest so that I connect to Host B directly.

linux

2 Answers

  1. Best Answer

    Are you aware that you type 4122 in the example?

    You should try 

    -L *:4420:172.88.3.31:22

    The star implies that you listen on all addresses, and not localhost, which you cannot connect to from other machines.

    You can also bind to a specific IP, but my guess is that * is what you want.

    • 8

    • Martin's answer should work.

      • -L *:4420:172.88.3.31:22
      • or -L 0.0.0.0:4420:172.88.3.31:22
      • or -L [specific IP]:4420:172.88.3.31:22

    • Another way:

      • -L -g 4420:172.88.3.31:22
      • Referenced from man ssh

        -g Allows remote hosts to connect to local forwarded ports. If used on a multiplexed connection, then this option must be specified on the master process.

    • 3