ssh remote port forwarding: connection refused

Trying to etablish remote ssh port forwarding:

On my remote host, /etc/ssh/sshd_config

GatewayPorts clientspecified

On my local computer:

ssh -g -R 1234:0.0.0.0:8000 me@my-remote-host

With debug, we can read:

debug1: Authentication succeeded (publickey).
Authenticated to s1.bux.fr ([178.32.223.76]:22).
debug1: Remote connections from LOCALHOST:1234 forwarded to local address 0.0.0.0:8000
debug2: fd 3 setting TCP_NODELAY
debug1: Requesting [email protected]
debug1: Entering interactive session.
debug1: remote forward success for: listen 1234, connect 0.0.0.0:8000
debug1: All remote forwarding requests processed

On remote host, we can contact 1234 port (WSGIServer/0.2 CPython/3.4.3 is the local machine 8000 port):

# http :1234
HTTP/1.0 302 Found
Content-Type: text/html; charset=utf-8
Date: Wed, 19 Oct 2016 13:26:00 GMT
Location: /accounts/login/
Server: WSGIServer/0.2 CPython/3.4.3
Vary: Cookie
X-Frame-Options: SAMEORIGIN

We can view opened port:

# netstat -tupln | grep 1234
tcp        0      0 127.0.0.1:1234          0.0.0.0:*               LISTEN      14460/1         
tcp6       0      0 ::1:1234                :::*                    LISTEN      14460/1

But, from another machine in world, i'm unable to contact my-remote-host:1324:

# http my-remote-host:1234

http: error: ConnectionError: HTTPConnectionPool(host='my-remote-host', port=1234): Max retries exceeded with url: / (Caused by NewConnectionError('<requests.packages.urllib3.connection.HTTPConnection object at 0xb6b2fbec>: Failed to establish a new connection: [Errno 111] Connection refused',)) while doing GET request to URL: http://my-remote-host:1234/

There is no firewall on my-remote-host:

# iptables -L
[sudo] password for bux: 
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
fail2ban-sshd  tcp  --  anywhere             anywhere             multiport dports ssh
fail2ban-ssh  tcp  --  anywhere             anywhere             multiport dports ssh

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination         

Chain fail2ban-ssh (1 references)
target     prot opt source               destination         
RETURN     all  --  anywhere             anywhere            

Chain fail2ban-sshd (1 references)
target     prot opt source               destination         
RETURN     all  --  anywhere             anywhere

How found where it's blocking ?

Solution 1:

tcp   0   0 127.0.0.1:1234    0.0.0.0:*               LISTEN   14460/1

Problem can be very well seen in the output of netstat. Your remote machine is listening on 127.0.0.1:1234, which is only available for local connection from that machine.

For ssh -g (gateway option) to work, you must specify wildcard address or some interface address reachable from the foreign client like:

ssh -g -R 0.0.0.0:1234:0.0.0.0:8000 me@my-remote-host

Solution 2:

Solution found is https://superuser.com/questions/588591/how-to-make-ssh-tunnel-open-to-public:

We have to set bind address like this:

ssh -R 0.0.0.0:1234:0.0.0.0:8000 me@my-remote-host

ssh remote port forwarding: connection refused

Solution 1:

Solution 2:

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