A virtual firewall appliance is a network firewall service that provides packet filtering inside a virtualized environment. A virtual firewall appliance oversees and controls approaching and outgoing traffic. A virtual firewall appliance works in conjunction with switches and servers like a physical firewall. A virtual firewall appliance keeps an unapproved user from getting to and transmitting information and records and virtual firewall appliance also prevents​ an organization's employee from exchanging any sensitive information or documents. A virtual firewall appliance works in two modes: bridge mode and hypervisor mode. Like a conventional firewall framework, bridge mode works by diagnosing and observing the majority of the virtual machines incoming and outgoing traffic. In hypervisor mode, the virtual firewall appliance works in isolation from the physical network, dwelling in the center hypervisor kernel and dealing with the incoming and outgoing traffic of the virtual machine.