How to install SSH server under Ubuntu

Since Xshell remote connection to Ubuntu is via SSH protocol, it is necessary to install an SSH server to Ubuntu.

1) Ubuntu installation SSH server

sudo apt-get install Openssh-server

2) If a problem occurs, restart the SSH service to

sudo service ssh restart

3) SSH Protocol Popular

Secure Shell(abbreviated as ssh), developed by the IETF Network Working group, which is a security protocol created on the application and transport layers, Provides a secure transport and usage environment for the shell (shell) on your computer.

Traditional Web service programs such as Rsh, FTP, pop, and telnet are inherently insecure because they transmit data, user accounts, and user passwords in plaintext over the network, and are vulnerable to an attack by a man-in-the-middle (man-in-the-middle) attack. Is that there is another person or a machine impersonating a real server to receive data from a user to the server, and then impersonating the user to pass the data to the real server.

SSH is now 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 allows you to encrypt all transmitted data, as well as to prevent DNS spoofing and IP spoofing.

Another advantage of SSH is that the data it transmits can be compressed, so it can speed up the transfer. SSH has many functions, which can replace Telnet and provide a secure "channel" for FTP, POP, and even PPP.

Reference website:

Https://zh.wikipedia.org/wiki/Secure_Shell

http://blog.csdn.net/tennysonsky/article/details/43489457

How to install SSH server under Ubuntu