Which of the following firewall implementations is a combination of a packet filter with bastion host?

The correct answer is the implementation known as a screened-host firewall. This type of firewall combines the functions of a packet filtering firewall with a bastion host that is directly configured to handle the traffic, providing enhanced security measures.

In a screened-host configuration, the packet filtering component acts as a first line of defense, evaluating and allowing or denying packets based on predefined security rules before they reach the bastion host. The bastion host itself is a fortified server that is designed to withstand attacks and provide an additional layer of security. This makes the screened-host configuration particularly resilient to various types of cyber threats since it incorporates both filtering capabilities and a robust host that can manage and analyze network traffic effectively.

This combination allows for not just basic filtering of packets but also for more comprehensive security by leveraging the bastion host's capabilities to handle traffic more securely, providing services directly while being protected from external threats.