This device is used between the zones with different security level, control the information exchanged between two networks, enforce the implementation of unified security policy, and prevent the…

This device is used between the zones with different security level, control the information exchanged between two networks, enforce the implementation of unified security policy, and prevent the intruder from copying and accessing the important information illegally. In short words, it protects the security of the system. Which of the following devices provides the function mentioned above?