Connect to a Linux EC2 instance in SSH mode with PuTTY

Download and install PuTTY from here.
Your EC2 instance muste have a public IP address (see Reserve and assign a static IP for an existing EC2 instance)
Get your EC2 public IP address : -> EC2 Dashboard -> Instances -> read the public IP on your instance line.
Port 22 must be open on your instance for ssh connection (see Open port 22 for ssh connection on an EC2 instance)
You must have a key pair attached to your instance (this is done at creation time see Create an EC2 instance in a public or private subnet)
Check your key pair name : EC2 Dashboard->Instances-> Read "Key Pair" line in "Description" pane
Make sure that you have the corresponing private key under format myKeyName.ppk. If you have the original .pem file, convert it (see Convert a .pem private key file to a .ppk one with PuTTYgen)
You must know the username with which you'll connect. It sounds obvious but unfortunately it depends on the AMI you have chosen at EC2 creation time. For "Amazon Linux 2 AMI (HVM), SSD Volume Type", it is ec2-user . For Ubunto distribution, it is ubuntu.
- In case you don't know the default user, check your AMI ID (EC2 Dashboard -> Instances -> Description tab) and search ! But usually it is ec2-user or root

Launch PuTTY
Enter your EC2 instance public IP address in "Host name field"
Make sure that Port is 22 and type is SSH
In the left pane, go to Connection->SSH->Auth to load your private key
Comme back to the Session pane
you probably want to save your parameters : enter a session name in "Saved sessions" field and click "Save"
click Open
do whatever you want with the security alert
enter your user name

You may start working !

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