I'm trying to establish a remote port forwarding to my Mac (target 4004) via a bastion host and Server-A to a Port (1555) on Server B.
So the whole connection is:
Mac:4004 => Bastion:22 => A:22 => B:1555
And the target is my Mac should have a Port 4004 forwarded from B:1555.
What is working so far?
I can connect to Server A with the command ssh user-bastion#user-A#server-A#server-bastion
On Server A I can establish a connection e.g. telnet to B:1555
On my windows client I can remote forward the port B:1555 to my local machine via Putty.
I'm now looking for the ssh command to establish this connection on my Mac.
Commands I tried:
Of course I have already searched for it and I've already tried different versions.
e.g.
ssh -fNT -R 1555:localhost:4004 -J user-bastion#user-A#server-A#server-bastion server-B
ssh -N user-bastion#user-A#server-A#server-bastion -R server-B:1555:localhost:4004
I always receive message like "Warning: remote port forwarding failed for listen port 1555"
Related
I'm trying to run a ssh SOCKS server on Windows 7 (listening on port 12345).
Here's the output I get on Cygwin:
$ ssh -v -D 12345 localhost
OpenSSH_6.8p1, OpenSSL 1.0.2c 12 Jun 2015
debug1: Reading configuration data /etc/ssh_config
debug1: Connecting to localhost [::1] port 22.
debug1: connect to address ::1 port 22: Connection refused
debug1: Connecting to localhost [127.0.0.1] port 22.
debug1: connect to address 127.0.0.1 port 22: Connection refused
ssh: connect to host localhost port 22: Connection refused
Why is it trying to connect to localhost:22?
Looks like it's trying to reach sshd running on localhost.
I thought the ssh client was enough to set up a local SOCKS server. If it isn't, why do I need sshd running?
From https://help.ubuntu.com/community/SSH/OpenSSH/PortForwarding:
"Dynamic port forwarding turns your SSH client into a SOCKS proxy server"
To explain why you need a (remote) ssh server, ssh can do three (or four) kinds of forwarding; quoting the man page:
-L Specifies that the given port on the local (client) host is to be
forwarded to the given host and port on the remote side. This
works by allocating a socket to listen to port on the local side,
optionally bound to the specified bind_address. Whenever a con-
nection is made to this port, the connection is forwarded over
the secure channel, and a connection is made to host port
hostport from the remote machine. [...]
-R Specifies that the given port on the remote (server) host is to
be forwarded to the given host and port on the local side. This
works by allocating a socket to listen to port on the remote
side, and whenever a connection is made to this port, the connec-
tion is forwarded over the secure channel, and a connection is
made to host port hostport from the local machine. [...]
-D 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 supported, and ssh will act
as a SOCKS server. [...]
-X and -Y enable forwarding for X11. This is a small but convenient variation of -R.
Note that in all cases the data is forwarded over the ssh tunnel, from the local machine to the ssh server or the reverse, and (therefore) the ssh tunnel must exist for the data to be forwarded over. The only difference between -L and -D is that -D uses SOCKS4/5 on the local end to specify where the remote end connects to.
If you want a SOCKS proxy that connects directly from the proxy to the destination, not over an ssh tunnel, you need a plain SOCKS proxy, not ssh+sshd.
Your trying to connect without a port. So port 22 is used. Once that connection is open then SSH will set up the socks proxy on the port you specified (12345)
You need to connect to a valid SSH server. You specify the port with the -p flag
I have remote host/server with ssh access.
I have my computer in my work network which can connect via ssh only
in within this network.
And i can not connect via ssh to other world because of port 22
blocked by firewall.
I am trying to create ssh tunnel to forward example localhost:80 to remote_server:22.(i suppose to connect via ssh to localhost and will be forwarded to my remote server)
I tried for example without proxy
sudo ssh -L localhost:443:remote_server_ip:22 root#remote_host_name
and with proxy
https://wiki.archlinux.org/index.php/Tunneling_SSH_through_HTTP_proxies_using_HTTP_Connect
I have read a lot and checked stackoverflow but it still is not clear for me how to resolve this issue.
I can now forward one port 8080 to the remote port 80 by ssh -L 8080:localhost:80 user#host.com, Is it possible to do multiple port forwarding with one ssh connection?
Yes, use -L option for each port to be forwarded.
Example:
ssh -L 8080:localhost:80 -L 7070:localhost:70 user#host.com
That is called dynamic port forwarding and if both the SSH server and SSH client support this, you configure your clients to use the SSH client as a SOCKS proxy and the SSH does the rest. In this case one "SSH connection" (in fact SSH connection carries multiple independent channels "inside") is used to connect to multiple destinations.
I have an Apache webserver running on a local machine through reverse ssh tunnel, i.e.:
ssh -R *:80:local_machine:8080 username#gateway_machine
In other words, all traffic from port 80 on gateway_machine
is sent to port 8080 on local_machine.
For monitoring purposes, I wish to know IP addresses of the remote clients
connected to gateway_machine. However my local Apache server sees
all traffic coming from the IP address of gateway_machine.
My question: Is there any way to setup ssh server running on gateway_machine such that
it sends all traffic to local_machine with actual remote IP addresses ?
The SSH protocol uses a channel type called "direct-tcpip" for forwarding a TCP connection. The protocol message for opening one of these channels includes the address and port of the client whose connection is being forwarded. So the information that you want is available to the ssh client (which in your case is opening the connection to the target of the forward).
The OpenSSH ssh client logs the originator address and port in a debug level message, so you can see it if you run ssh with the -v option:
$ ssh -v -R 2000:localhost:1000 localhost
...
debug1: client_request_forwarded_tcpip: listen localhost port 2000, originator ::1 port 51101
Here the originator address was ::1 (IPv6 localhost) and port 51101. The ssh utility doesn't do anything else with the information.
So, depending on your needs, you have three approaches to collect this information:
Invoke the ssh process which creates these forwards with the -v option, and arrange to collect and parse the relevant debug information.
Make source code changes to ssh to make it do what you want it to do with the information.
Write your own ssh client which does what you want. SSH client libraries are available for most modern programming languages.
i using mac os..
i tried
ssh -fNg -L 5985:127.0.0.1:5984 wawansetiawan#192.168.1.249
but there's command like this:
bind: Address already in use
channel_setup_fwd_listener: cannot listen to port: 5985
Could not request local forwarding.
any one can help me??
This is nothing to do with couchdb, it's an ssh question. ssh cannot open port 5985 because there's already something running on your local machine listening on that port. Use a different port or close whatever process has port 5985 open.
An application/Process is already running on your machine with port 5985. Use a different port or close whatever application/process has port 5985 & start the ssh tunnel again.
Try to use different port
ssh -fNg -L 5986:127.0.0.1:5984 wawansetiawan#192.168.1.249
Or You can kill application/process has port 5985.
netstat -nap | grep 5985
kill -9 <pid-of-5985-process>
Start the ssh tunnel again.
ssh -fNg -L 5985:127.0.0.1:5984 wawansetiawan#192.168.1.249