SSH (Secure Shell) in AWS refers to the Secure Shell protocol used for securely accessing and managing EC2 instances or other resources within the AWS environment.
Here’s how SSH is typically used in AWS:
- Accessing EC2 Instances: After launching an EC2 instance, you may need to connect to it for configuration, administration, or troubleshooting purposes. SSH provides a secure way to remotely access the command-line interface of the instance.
- Key-Based Authentication: AWS uses key pairs for SSH authentication. When launching an EC2 instance, you specify a key pair, and AWS stores the public key on the instance. You then use the corresponding private key to authenticate when connecting via SSH.
- Security: SSH connections in AWS are encrypted, providing a secure method for accessing your EC2 instances over the internet.
- Port: By default, SSH operates on port 22. You need to ensure that your security group rules allow inbound traffic on port 22 from your IP address or a range of IP addresses you trust.
- SSH Bastion Hosts: In more complex architectures, you might use SSH bastion hosts (also known as jump hosts or bastion servers) as an intermediary for accessing private instances located in a private subnet. This adds an additional layer of security by controlling access to the private instances.
- SSH Agent Forwarding: AWS also supports SSH agent forwarding, which allows you to use your local SSH key pair to authenticate to instances without storing the private key on the instance itself. This can be useful for scenarios where you need to access multiple instances from a single local workstation.
Overall, SSH plays a crucial role in managing and accessing EC2 instances securely within the AWS environment, providing administrators with a powerful tool for remote administration and configuration.