User's Manual

Contents iii
Chapter 7 
Troubleshooting...................................................................................................................7-1
Basic Functions ..............................................................................................................7-1
Power LED Not On ...................................................................................................7-2
Test LED Stays On ...................................................................................................7-2
Local Link LEDs Not On ...........................................................................................7-2
Cable Link LED Not On ............................................................................................7-3
Troubleshooting the Web Configuration Interface ..........................................................7-3
Troubleshooting the ISP Connection ..............................................................................7-4
Troubleshooting a TCP/IP Network Using a Ping Utility .................................................7-4
Testing the LAN Path to Your Gateway ....................................................................7-4
Testing the Path from Your PC to a Remote Device ................................................7-5
Appendix A 
Technical Specifications .................................................................................................... A-1
Appendix B 
Networks, Routing, and Firewall Basics........................................................................... A-1
Related Publications ...................................................................................................... A-1
Basic Router Concepts .................................................................................................. A-1
What is a Router? ................................................................................................... A-2
Routing Information Protocol ................................................................................... A-2
IP Addresses and the Internet ................................................................................. A-2
Netmask .................................................................................................................. A-4
Subnet Addressing .................................................................................................. A-5
Private IP Addresses ............................................................................................... A-7
Single IP Address Operation Using NAT ................................................................. A-8
MAC Addresses and Address Resolution Protocol ................................................. A-9
Related Documents ................................................................................................. A-9
Domain Name Server ............................................................................................ A-10
IP Configuration by DHCP .................................................................................... A-10
Internet Security and Firewalls .................................................................................... A-10
What is a Firewall? .................................................................................................A-11
Stateful Packet Inspection ......................................................................................A-11
Denial of Service Attack .........................................................................................A-11
Wireless Networking Overview .................................................................................... A-12
Infrastructure Mode ............................................................................................... A-12