Network firewalls are security devices used to stop or mitigate（ ） access to private networks connected to the lnternet, especially intranets. The only traffic allowed on the network is defined via firewall （ ）-any other traffic attempting to access the network is blocked. Network firewalls sit at the （ ） line of a network, acting as a communications liaison between internal and external devices, When properly configured, a firewall allows users to access any of the resources they need while simultaneously keeping out unwanted accesses. In addition to limiting access to a protected computer and network, a firewall can （ ） all traffic coming into or leaving a network, and manage remote access to a private network through secure authentication certificates and logins. （ ） firewalls examine every packet that passes through the network and then accept or deny it as defined by rules set by the user.