The syntax is: ssh -L local_port:remote_address:remote_port example, let’s say the database server at your office is located at 192.168.1.111 on the office network. To use local forwarding, connect to the SSH server normally, but also supply the -L argument. You can use any command line or graphical tool to access the database server as if it was running on your local PC. The SSH server sits in the middle, forwarding traffic back and forth. So, when you attempt to access the database server at port 1234 your current PC, “localhost”, that traffic is automatically “tunneled” over the SSH connection and sent to the database server.
#Ubuntu ssh tunnel manager how to#
Using Socks Proxy on iOSĬheck How to Configure iOS to Use Socks Proxy over SSH with a Linux/Unix Host.To do this, you establish an SSH connection with the SSH server and tell the client to forward traffic from a specific port from your local PC-for example, port 1234-to the address of the database’s server and its port on the office network. If you are using Linux with NetworkManager, it is very convenient to set up the global proxy of GNOME to use the socks proxy created by SSH.Ĭreating and Using Socks Proxy on WindowsĬheck Proxy Using SSH Tunnel. Now we can port forwards port 8080 on localhost to it by this: $ ssh -L 8080:proxy:port Global Proxy in GNOME with NetworkManager on Linux For example, the proxy server and port is proxy:port. I only provides a simple example here, while more details of ssh port forwarding can be found from Port Forwarding using ssh Tunnel. But the connection between the client and the other kind of proxy server such as squid can also make use of ssh tunnel. This post mainly focus on using ssh to build up the proxy system.
Or let it run in the shell: $ ssh -CTND 8080 can also configure it to listen on all addresses on the host by: I like to use this combination: $ ssh -CnfND 8080 I want to close the ssh proxy tunnel, I need to find the pid of it by $ ps aux | grep ssh These arguments can be used with -D for different usages. Causes most warning and diagnostic messages to be suppressed. n Redirects stdin from /dev/null (actually, prevents reading from stdin). f Requests ssh to go to background just before command execution. This is useful for just forwarding ports. There are some other ssh arguments that can make the port forwarding more convenient for us: -C Requests gzip compression of all data The command is: $ ssh -D s1_ip:p1 command sets up a socks5 proxy server on s1. Users (and include yourself of course) can use this socks5 proxy with address s1_ip and port p1. This kind of proxy server can provide service to other users. After setting up this proxy tunnel, set the proxy option in browser to 127.0.0.1:p1 and using socks5. Any port larger than 1024 can be chosen as p1. The command is: $ ssh -D p1 is the port on localhost. c0 and s1 in the graph above are the same machine. This proxy server can only be used on localhost, which means the other users can not use it. 1) Proxy listening to localhost port only Whenever a connection is made to this port, the connection is forwarded over the ssh channel, and the application protocol is then used to determine where to connect to from the remote machine. ssh allocates a socket to listen to port on the local side, optionally bound to the specified ip address. This uses ssh’s “dynamic” port forwarding function by using parameter “-D”. Now let’s look at how to set up proxy by using ssh tunnel. Using ssh as a proxy to browse the web is very useful under some situation: Local access restriction such as behind a strict firewall in some country, company or school You are in a insecure network environment while you want to login to your account. Maybe most of the time c0 and s1 are the same machines as the simple example at the beginning of the post. The overall system can be shown as this: c0:p0 s1:p1 s2:p2 s3 s1 will act as the proxy server, while s2 connects to the service provider (s3).
Then we can set up a proxy server system using ssh tunnel. For example, we have a sshd server s2 and another server s1 as the proxy server. We can set up a more complex proxy server through ssh.