A firewall is a physical device or software program that examines data packets on a network to determine whether to either forward them to their destination or block them. A firewall can be a one-way firewall, which protects against inbound threats only, or a two-way firewall, which protects against both unauthorized inbound and outbound traffic. Most third-party firewall programs, such as ZoneAlarm, are two-way firewalls. A software firewall can be configured to permit traffic between specified IP addresses and to block traffic to and from the Internet except when permitted on a per-program basis.
A corporate network can use a proxy server with a firewall as the sole direct connection between the Internet and the corporate network and then use a firewall in the proxy server to protect the corporate network against threats.
Physical firewalls are specialized computers whose software is designed to quickly analyze network traffic and make forwarding decisions based on rules set by the administrator. Over time, that task has been incorporated more into software on the computers and into the OS design. An example is Windows Defender Firewall in Windows, which is discussed in the section, “Microsoft Windows OS Security Settings.”
0 comments:
Post a Comment