SSH (Secure Shell protocol)

SSH is the abbreviation for secure Shell, developed by the IETF Network Working Group, and SSH is a security protocol based on the application layer and transport layer. SSH is currently a more reliable protocol that provides security for Telnet sessions and other network services. The use of SSH protocol can effectively prevent the information leakage in the remote management process. SSH was originally a program on a UNIX system, and later expanded quickly to other operating platforms. SSH can compensate for vulnerabilities in the network when it is used correctly. The SSH client is available on a variety of platforms. Almost all UNIX platforms-including HP-UX, Linux, AIX, Solaris, Digital UNIX, Irix, and other platforms-can run SSH.

Install in Ubuntu

Buntu default does not install the SSH service, if the SSH link to Ubuntu, you need to manually install the Ssh-server, but SSH sub-client openssh-client and server openssh-server,openssh- Client is clients, Openssh-server is the server,

What we're talking about here is the server that installs SSH, namely: Openssh-server.

To determine if our machine has SSH service installed, you can use the following command:

SSH localhost
Ssh:connect to host localhost Port 22:connection refused

This means that no SSH has been installed,

Install command: sudo apt-get install Openssh-server

Uninstall command: sudo apt-get remove openssh-server

After we run the sudo apt-get install openssh-server command, confirm that the installation is OK

Ps-e|grep SSH

1418? 00:00:00 sshd

See sshd That means Ssh-server's started.

If not, you can start this way: sudo/etc/init.d/ssh start or service ssh start

Prior to installing SSH for the experiment, install and uninstall the prompt: E:unable to locate package opensshe:unable to locate packages server This is a warning that this is not found in the OpenSSH of the installation pack, Before you can install the instructions SSH package is present, and after uninstalling but prompted not to find the SSH package, it is likely to be run uninstall, directly deleted, then we need to upgrade the sudo apt-get update, and then install the test or not. And then looked online to say is updated the software source, need to update and install before you can use the installation update
sudo apt-get dist-upgrade

If you need a new user to connect

New user AddUser test will then ask you to fill in the password, you can also switch to the user to change the password, and then use passwd to change the password

SSH (Secure Shell protocol)