The ADSL2+ Ethernet/USB Router's firewall inspects packets at the application layer, maintains TCP and UDP session information, including time-outs and the number of active sessions, and provides the ability to detect and prevent certain types of network attacks.

Network attacks that deny access to a network device are called Denial-of-Service (DoS) attacks. DoS attacks are aimed at devices and networks with a connection to the Internet. Their goal is not to steal information, but to disable a device or network so users no longer have access to network resources.

The ADSL2+ Ethernet/USB Router firewall function protects against the following DoS attacks: IP Spoofing, Land Attack, Ping of Death, IP with zero length, Smurf Attack, UDP port loopback, Snork Attack, TCP null scan, and TCP SYN flooding.

Note: The firewall does not significantly affect system performance, so we advise enabling the prevention features to protect your network.

To enable the firewall:

1. Click FIREWALL.
2. Select Enable.
3. Click SAVE SETTINGS. You can now configure your firewall options by clicking any of the following in the WUI:
   - Access Control
   - MAC Filter
   - URL Blocking
   - Schedule Rule
   - Intrusion Detection
   - DMZ