Linux Classroom Series – 31/Jul/2020

Constructing SSH Command

• SSH Command is quite simple

# This will ask password
ssh username@<hostname/ip-address>

# If you are using key based authentication
ssh -i <path-to-key> username@<hostname/ip-address>

• By default ssh runs on port 22, if ssh runs on any other port (8922)

ssh -p 8922 username@<hostname/ip-address>
ssh -p 8922 -i <path-to-key> username@<hostname/ip-address>

• To run ssh command we need ssh client
  • In linux & MAC machines we already have terminal with ssh clients
  • Windows:
    1. Latest Windows 10 or windows 2016 server or later: Microsoft has added ssh client and you can use it from powershell
    2. You need to install ssh clients like
       • Git Bash
       • Putty
       • Cygwin
• There is one file where ssh server configuration will be present on the linux machine (/etc/ssh/sshd_config)
• Now lets try to create a some user on centos machine

sudo adduser linuxadmin
sudo passwd linuxadmin
sudo usermod -aG wheel linuxadmin

• Now lets try to generate key pairs on the ubuntu machine for the new user called as linuxadmin

sudo adduser linuxadmin
sudo usermod -aG sudo linuxadmin
ssh-keygen
ssh-copy-id linuxadmin@<centosip>
ssh centosip