Non-routing dual-homed hosts are the type of bastion hosts configured by Elliott in the above scenario. A bastion host is a system or device that is exposed to the public internet and acts as a gateway or a proxy for other systems or networks behind it. A bastion host can be used to provide an additional layer of security and protection for internal systems or networks from external threats and attacks . A bastion host can have different types based on its configuration or functionality. A non-routing dual-homed host is a type of bastion host that has two network interfaces: one connected to the public internet and one connected to the internal network. A non-routing dual-homed host does not allow any direct communication between the two networks and only allows specific services or applications to pass through it . A non-routing dual-homed host can be used to isolate and secure internal systems or networks from external access . In the scenario, Elliott was appointed to test a newly developed application deployed over an organizational network using a bastion host. Elliott initiated the process by configuring the non-reusable bastion host. He then tested the newly developed application to identify the presence of security flaws that were not yet known; further, he executed services that were not secure. This means that he configured a non-routing dual-homed host for this purpose. An external services host is a type of bastion host that provides external services, such as web,email, FTP, etc., to the public internet while protecting internal systems or networks from direct access . A victim machine is not a type of bastion host, but a term that describes a system or device that has been compromised or infected by an attacker or malware . A one-box firewall is not a type of bastion host, but a term that describes a firewall that performs both packet filtering and application proxy functions in one device .