This slide looks at two methods to prevent intruders from accessing private networks. To create a strong firewall, an administrator must maintain detailed internal rules identifying the people, applications, or addresses that are allowed or rejected. Firewalls can deter, but not completely prevent, network penetration by outsiders and should be viewed as one element in an overall security plan.
Ask students to differentiate between the screening technologies listed here. Note that these are often used in combination. Ask students if they use firewall software on their own computers.