User's Manual

F5D8230-4 user draft.doc Page 42 of 89
Configuring the Firewall
Your Router is equipped with a firewall that will protect your network from a wide array of
common hacker attacks including:
• IP Spoofing
• Land Attack Ping of Death (PoD)
• Denial of Service (DoS)
• IP with zero length
• Smurf Attack
• TCP Null Scan
• SYN flood
• UDP flooding
• Tear Drop Attack
• ICMP defect
• RIP defect
• Fragment flooding
•
The firewall also masks common ports that are frequently used to attack networks. These ports
appear to be “stealth” meaning that for all intents and purposes, they do not exist to a would-be
hacker. You can turn the firewall function off if needed; however, it is recommended that you
leave the firewall enabled. Disabling the firewall protection will not leave your network completely
vulnerable to hacker attacks, but it is recommended that you leave the firewall enabled.
[firewall.tif]
Configuring Internal Forwarding Settings
The Virtual Servers function will allow you to route external (Internet) calls for services such as a
web server (port 80), FTP server (Port 21), or other applications through your Router to your
internal network. Since your internal computers are protected by a firewall, computers outside
your network (over the Internet) cannot get to them because they cannot be “seen”. A list of
common applications has been provided in case you need to configure the Virtual Server function
for a specific application. If your application is not listed, you will need to contact the application
vendor to find out which port settings you need.