LINUX-SSH Overview and Configuration

First, brief

Authentication and encryption method of SSH connection

The SSH connection is the CS model (client-server), the client makes the connection request, the server authenticates the client, and then considers whether to accept the connection request.

The theoretical basis of SSH's secure encryption method is asymmetric encryption system. In the asymmetric encryption, the common one is the RSA encryption algorithm. When using SSH, it is important to first clarify the asymmetric encryption and RSA algorithm flow. See RSA encryption Algorithm for details.

SSH has two levels of security authentication: account password verification, RSA encryption authentication. Detailed parameters can be set in the Sshd_config configuration file (Ubuntu is/etc/ssh/sshd_config,mac under/etc/sshd_config)

Second, install the configuration ssh

See if SSH has been installed

1. Rpm-qa | grep ssh

If no installation is used

2.yum Install SSH

After installation, turn on SSH service.

3.service sshd Start

or use/etc/init.d/sshd start

So you can already use some of the SSH commands, ssh default port is 22, if you need to modify

Vim/etc/ssh/sshd_config

Modify the ports behind the port to

If you need to connect to SSH remotely, you need to open the 22 port on the firewall.

Here first try service iptables stop firewall

LINUX-SSH Overview and Configuration