CODEWITHSUNDEEP
dockersshportforwardingopensshalpine-linux
ChrKong
ChrKong

Reputation: 111

Docker SSH forwarding - bind: Address not available

I have a Docker container, which I would like to be able to interact with a database trough a SSH tunnel.

My Docker image is built on an alpine image and in the Dockerfile I have installed openssh-client and exposed port 27017

When I spin up my Docker image and try to forward the ports with:

ssh -i /.ssh/ssh_key user@remote_ip -L 27017:localhost:27017 -Nf

I get an error:

bind: Address not available

It is not a problem to ssh into the remote server, but I am not able to forward the ports.

Thanks

Upvotes: 11

Views: 8927

Answers (2)

Elijah Lynn
Elijah Lynn

Reputation: 13498

You can get a "bind address not available" if you don't specify which interface you want to use. By default it will use all of them, including IPV6. In my case, it was binding on IPV4 but the "address not available" was actually for IPV6 e.g. bind [::1]:2001: Address not available. If you use the -4 option, this will use IPV4 only and if you were getting an IPV6 type error, then this will resolve that for you, which it was for me on Arch Linux.

-4 Forces ssh to use IPv4 addresses only.

-D [bind_address:]port

   Specifies a local “dynamic” application-level port forwarding.  This works by allocating a
    socket to listen to port on the local side, optionally bound to the specified
    bind_address.  Whenever a connection is made to this port, the connection is forwarded
    over the secure channel, and the application protocol is then used to determine where to
    connect to from the remote machine.  Currently the SOCKS4 and SOCKS5 protocols are sup‐
    ported, and ssh will act as a SOCKS server.  Only root can forward privileged ports.
    Dynamic port forwardings can also be specified in the configuration file.

   IPv6 addresses can be specified by enclosing the address in square brackets.  Only the
    superuser can forward privileged ports.  By default, the local port is bound in accordance
    with the GatewayPorts setting.  However, an explicit bind_address may be used to bind the
    connection to a specific address.  The bind_address of “localhost” indicates that the lis‐
    tening port be bound for local use only, while an empty address or ‘*’ indicates that the
    port should be available from all interfaces.

Upvotes: 6

ssh_tunnel
ssh_tunnel

Reputation: 91

I manage to create a ssh tunnel from a docker-compose using this entrypoint:

ssh -4 -i /.ssh/ssh_key -NL *:27017:0.0.0.0:27017 user@remote_ip


and then i was able to use the ssh tunnel from an another container by using the network created with the docker-compose

docker run --network=tunnel_default image nmap -p 27027 service_name


tunnel_default is the name of the network

image is a docker image where nmap is installed (it allows you to check open ports)

service_name is the name i gave to the service inside the docker-compose

Upvotes: 9

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