A. Frame filter
B. Packet filter
C. From the dangers of unknown resources on the internet and other network connections that may be harmful. the firewall prevents unauthorized access to your internal, trusted network from outside threats.
D. Content filter
Explanation: As you know, firewalls are available as hardware appliances, as software-only, or a combination of the two. In every case, the purpose of a firewall is to isolate your trusted internal network (or your personal PC) from the dangers of unknown resources on the Internet and other network connections that may be harmful. The firewall prevents unauthorized access to your internal, trusted network from outside threats.
A. Stateful firewall and stateless firewall
B. Bit oriented firewall and byte oriented firewall
C. Frame firewall and packet firewall
D. Network firewall and data firewall
Explanation: Most network layer firewalls can operate as stateful or stateless firewalls, creating two subcategories of the standard network layer firewall. Stateful firewalls have the advantage of being able to track packets over a period of time for greater analysis and accuracy — but they require more memory and operate more slowly. Stateless firewalls do not analyze past traffic and can be useful for systems where speed is more important than security, or for systems that have very specific and limited needs. For example, a computer that only needs to connect to a particular backup server does not need the extra security of a stateful firewall.