Gateway: A gateway is a network device that is typically used to connect two different networks and act as an intermediary for data transfer. Firewall: is a network security device or software used to protect a network from unauthorized access and malicious attacks. Gatekeeper: A gatekeeper is a network security device used to isolate different networks and prevent potential network attacks and threats.

Firewall is a kind of high performance hardware firewall, compared with other hardware firewall has essential difference.Actually,other hardware firewall is running a software firewall on PC platform, and the firewall is by ASIC chip to carry out the strategy of firewall and data encryption, so it's much faster than other firewalls. From software features, the firewall is a combination of state detection and application agent, for most of the applications of a firewall is monitoring the whole communication state,if the communication state is found to be abnormal, it wil refuse to enter a protected internal network, for FTP or H322 and other communication status is not well tracked service,the firewall by applying the agent to ensure the security of the service.

Bypass, as the name implies, is a "bypass" function, that is, through a specific trigger state (power off or crash), the two pNIC Ports (physical network card ports) can be connected directly at the pNIC level without going through the intermediate system (e.g. operating system).