An Amazon Web Services (AWS) Bastion host is a special type of EC2 instance that is used to securely connect to other resources in your AWS environment. A Bastion host is typically used as a jump box, allowing you to securely connect to resources within your VPC without exposing them directly to the internet. 

One of the key benefits of using a Bastion host is that it allows you to secure your resources by limiting inbound traffic to only the traffic that is needed. For example, you might allow only SSH or Remote Desktop Protocol (RDP) traffic to your Bastion host, and then use the Bastion host to connect to your other resources. This can help to reduce the attack surface of your resources and make them more secure. 

To use a Bastion host, you will need to launch an EC2 instance and configure it as a Bastion host. This typically involves configuring the security group and network ACLs for the Bastion host to allow only the traffic that is needed, such as SSH or RDP traffic.
You will also need to configure your VPC routing tables to route traffic to the Bastion host. 

Once your Bastion host is configured, you can use it to securely connect to your other resources. For example, you might use SSH to connect to your Bastion host from your local machine, and then use the Bastion host to connect to your other resources using Remote Desktop Protocol (RDP) or Secure Shell (SSH). 

Overall, an AWS Bastion host is useful for securely connecting to resources in your AWS environment. It allows you to limit inbound traffic to only the traffic that is needed, reducing the attack surface of your resources and making them more secure.