In the AWS shared responsibility model, the customer is responsible for managing the security configuration of the services they use. This includes setting up and configuring firewalls for the virtual servers. AWS takes responsibility for the underlying infrastructure and managed services, whereas tasks like encrypting data in transit and at rest might be configured by the customer, but leveraging tools and features provided by AWS. The key here is that the customer must handle the security on the 'guest' operating system level, including firewall configuration, which is not the same as physical or environmental security handled by AWS.