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Firewall Help
NAT and Firewall service The DSL Router uses Network Address Translation (NAT) and Stateful Packet Inspection (SPI) Firewall to protect your home network. The NAT and Firewall Service can be globally (for LAN and all WAN connections) disabled/enabled from the Setup Firewall/NAT Service page. If disabled no NAT functionality nor firewall protection can be provided. For each WAN connection (e.g. the Internet connection) NAT and Firewall (SPI) can be enabled/disabled. With Firewall (SPI) enabled on a WAN connection all incoming packets are examined by the Stateful Packet Inspection engine and traffic is dropped if it is not matching an existing connection opened from LAN side or a port forwarding rule. Connections from LAN side to the Internet are trusted and allowed to pass thru the router unless explicit IP Filter rules are used to block the LAN traffic. This Asymetric Permisive Firewall setup (drop from WAN, allow from LAN) provides easy to use Internet access while protecting the home network.
Port Forwarding Using the Port Forwarding page, you can provide local services (for example web hosting) for people on the Internet or play Internet games. To configure a service, game or other application select the external connection (for example the Internet connection), select the computer hosting the service and add the corresponding firewall rule. If you want to add a custom application, select the User category, click New and fill in the port, protocols and description for your application. You can also add/edit/delete rules without using the pre-defined Firewall Policy Database (games, services, etc.). Click on "Custom Rules" to access this type of interface. In the presence of the firewall, anonymous Internet traffic is blocked.
IP Filters This firewall feature allows you to block network access based on a user's computer IP address. You can use this page to block specific traffic (for example block web access) or any traffic from a computer on your local network. To configure an IP Filter rule select the computers' IP address and add the corresponding firewall traffic definition from the Firewall Policy Database. If the traffic type is set to "Any" all network traffic from that computer will be blocked. You can also add/edit/delete IP FIlter rules without using the pre-defined Firewall Policy Database (games, services, etc.). Click on "Custom Rules" to access this type of interface.
Access Control Open the access from the Internet (WAN) or LAN to the router's management ports (web, telnet, ssh, ftp, tftp, snmp). There are security risks associated with this action. For this reason remote management is restricted to computers on the network specified in the IP Access Control List that can hold up to 16 IP addresses. The Access Control List provides a global enable/disable that will enable or disable the ACL. If the ACL is disabled, the default behaviour (i.e. DENY on the WAN, Accept on the LAN is enabled for all IP addresses) is enforced. If no IP addresses are specified within the ACL, the ACL will be will act as if it is disabled until the first IP address is added.
DMZ Setting a computer on your local network as DMZ forwards any network traffic that is not redirected to another computer via the port forwarding feature to the computer's IP address. This opens the access to the DMZ computer from the Internet.
PING Enabling incoming ping (ICMP) requests on the Port Forwarding page allows the router to respond to a ping from the Internet. Blocking outgoing ping (ICMP) (IP Filters page) generated from a particular LAN IP can be used if your PC has a virus that attempts a Ping-of-Death Denial of Service attack.