D-Link DSL-504T Product Manual - Page 67

DSL-504T User's Manual Advanced - Firewall Advanced-Firewall (continued) When DoS, Port Scan, or Service Filtering Protection is enabled, it will create a firewall policy to protect your network against the following: Dos Protection SYN Flood check ICMP Redirection check Port Scan Protection Nmap/FIN attack URG/PSH attack Xmas Tree Scan Null Scan attack SYN/RST attack Service Filtering Ping from WAN Telnet from WAN FTP from WAN DNS from WAN IKE from WAN RIP from WAN DHCP from WAN A DoS "denial-of-service" attack is characterized by an explicit attempt by attackers to prevent legitimate users of a service from using that service. Examples include: attempts to "flood" a network, thereby preventing legitimate network traffic, attempts to disrupt connections between two machines, thereby preventing access to a service, attempts to prevent a particular individual from accessing a service, or, attempts to disrupt service to a specific system or person. Port scan protection is designed to block attempts to discover vulnerable ports or services that might be exploited in an attack from the WAN. The Service Filtering options allow you to block FTP, Telnet response, Pings, etc, from the external network. Check the category you want to block to enable filtering of that type of packet. When you have selected the desired Firewall policies, click the Apply button to enforce the policies. Remember to save any configuration changes. D-Link Systems, Inc. 67