ZyXEL ZYWALL USG 20W User Guide - Page 38

Chapter 2 Features and Applications Firewall The ZyWALL's firewall is a stateful inspection firewall. The ZyWALL restricts access by screening data packets against defined access rules. It can also inspect sessions. For example, traffic from one zone is not allowed unless it is initiated by a computer in another zone first. Anomaly Detection and Prevention (ADP) ADP (Anomaly Detection and Prevention) can detect malicious or suspicious packets and respond instantaneously. It can detect: • Anomalies based on violations of protocol standards (RFCs - Requests for Comments) • Abnormal flows such as port scans. The ZyWALL's ADP protects against network-based intrusions. See Section 29.3.4 on page 472 and Section 29.3.5 on page 475 for more on the kinds of attacks that the ZyWALL can protect against. You can also create your own custom ADP rules. Bandwidth Management Bandwidth management allows you to allocate network resources according to defined policies. This policy-based bandwidth allocation helps your network to better handle applications such as Internet access, e-mail, Voice-over-IP (VoIP), video conferencing and other business-critical applications. Content Filter Content filtering allows schools and businesses to create and enforce Internet access policies tailored to the needs of the organization. You can also subscribe to category-based content filtering that allows your ZyWALL to check web sites against an external database of dynamically-updated ratings of millions of web sites. You then simply select categories to block or monitor, such as pornography or racial intolerance, from a pre-defined list. Anti-Spam The anti-spam feature can mark or discard spam. Use the white list to identify legitimate e-mail. Use the black list to identify spam e-mail. The ZyWALL can also check e-mail against a DNS black list (DNSBL) of IP addresses of servers that are suspected of being used by spammers. 38 ZyWALL USG 20/20W User's Guide