SSH and Basic Commands to Handle VPS

1. SSH (Secure Shell) protocol uses encryption to secure connection between client and a server. User authentication, file transfers, output and commands are encrypted to protect against cyber-attacks across the network. SSH, a secure channel, connects SSH client with a server. SSH has two major versions, SSH-1 and SSH-2. The standard SSH port is 22. SSH is generally used to excess Unix OS. But it can also be used to excess Microsoft Windows. Latest OS Windows 10 uses OpenSSH client as default. SSH was designed to replace Telnet and for other unsecure remote shell protocols, such as Berkeley rsh and rexec protocols. These protocols are very unsecure as they send sensitive information, such as passwords, in plaintext. Attacker can see passwords while analyzing data packets. SSH uses public key cryptography to authenticate remote computer and after authentication it allows it to connect. There are several other ways to connect SSH. One is to automatically generate public-private key pairs to encrypt network connection and use password to authenticate. Another way is to manually generate public-private key pair to perform authentication. This allows users to log in without having specific passwords. In this scenario, any user can produce matching pair of public and private keys. The public key is stored on all computers that allow access to the owner of the matching private key. While authentication is based on private key, the key is never transferred via network during authentication. SSH only verifies the entity that offers public key, matching the private key. In every version, SSH is important to authenticate public key. It is important to verify unknown public key before accepting it. Without validation, it could probably be an attacker’s public key. Top SSH Clients: -

2. •SolarPuTTY •PuTTY •SecureCRT •SmarTTY •mRemoteNG •MobaXterm Common Usage of SSH protocol: - •SSH is mostly used in corporate networks •To provide secure access in automation processes and to users •Fast, automated and interactive file transfers •To execute remote commands •To manage network infrastructure and critical system components Enabling SSH: - To create SSH connection, the client and the server component, both need to be installed on local and remote machine. There are many open source SSH tools that are widely used in Linux distribution. OpenSSH is very easy to use. It requires access to terminal on the server and the computer that use it for connecting. Opening SSH in Linux: - •Open terminal in server machine. You can search terminal or press keys – CTRL+ALT+T on keyboard. •Type SSH localhost and press enter. For checking if the service is running or not: - •Type sudo service ssh status •Then type ssh localhost and now you can accept SSH connections. Commands to handle VPS: - •Command – top Top is used to see all running processes. •Command – ps Ps is similar to top. It shows the list of running processes. •Command –free Free is used to view data in physical memory. •Command – df Df is used to list server partitions. •Command – w W is used to list users connected with the server •Command – cd

3. Cd is used to navigate to directories. •Command – mkdir Mkdir is used to create directories. •Command –cp Cp is used to copy directories. •Command – ls Ls is used to list content in the present directory. •Command – rm Rm is used to remove files. •Command –mv Mv is used to move files and directories. •Command – chmod Chmod is used to change permission of files and folders. •Command –tar Tar is used to compress/ decompress files. The common commands used in every Linux distribution have been mentioned above. Source:https://htshosting.org/blog/2021/05/ssh-basic-commands-to-handle-vps/