Beyond Security: OpenSSH skills

OpenSSH is an important remote management tool on Linux and is known for its security. It is believed that most users are already familiar with the use of openssh, such as using SSH for remote connections, using SCP, sftp copying files, and so on. But the power of OpenSSH is much more than that, and we will show you the following.

1.x11 forwarding

Using the-X option, you can display GUI programs on remote Linux locally. Log on to the remote system and enable X11 forwarding you can use the following command:

Of course, the x11forwarding parameter of the target system profile/etc/ssh/sshd_config should be set to Yes and the OpenSSH daemon should run.

2. Through the firewall

Beware of malicious attacks similar to firesheep in public networks. A good security approach is to use SSL/HTTPS encryption instead of using plaintext to send information.

We have another option. If we want to avoid firewalls configured to disallow the use of the HTTP/SMTP protocol and establish an SSH security channel, you can use the following command:

Ports can be adjusted arbitrarily to avoid conflicts with other services.

3. Execute remote command

You do not have to log on, or you can execute commands on the remote system. For example, you can check disk space with the following command:

We can even use pipelines, for example:

4. Port forwarding

Now let's discuss the topic of port forwarding. OpenSSH port forwarding is divided into local port forwarding and remote port forwarding, which differs in the direction of port mapping. We use port forwarding to easily bypass firewalls. For example, suppose your work network does not allow access to reddit.com. Please run:

This allows us to access reddit.com indirectly through "YourServer". If you use the-g parameter, you can allow other computers in the workspace to access reddit.com through your computer:

5.SSH File System

Through the fuse project and the SSHFS project, we can talk about remote SSH mount to local. FUSE4X can be used on Mac platforms.

You can use the following command to simplify the installation of SSHFS:

We can use the following command to mount:

OpenSSH There are many powerful functions to be excavated, welcome to put forward their own views. (Zhang Zhiping/compiling)

(Responsible editor: The good of the Legacy)