How to Troubleshoot LAN, WAN and PAN Internet Connections
By Dave Wilson
Network equipment and medium varies widely between WAN (Wide Area Network), LAN (Local Area Network) and PAN (Personal Area Network) connections. However, if they all have connections to the Internet, then they all have TCP/IP as a common protocol that can be used to test connectivity on each network. Run "ping" and "tracert" utilities in Microsoft Windows 7 to troubleshoot connectivity issues on networks connected to the Internet.
Start the Windows 7-run computer, and select the "Programs" icon. Then select "Accessories." Right-click on the command line item in the menu that appears, and click "Run as Administrator."
Enter "ping 127.0.0.1" in the command line window that appears. Tap the "Enter" key. Confirm that four replies are displayed in the command line output and proceed to the next step. Otherwise, reinstall the network adapter drivers, reboot the computer and then repeat the ping test before proceeding to the next step.
Enter "ipconfig /all," and tap the "Enter" key. Inspect the command line output. If the network adapter that provides Internet access displays "0.0.0.0" or begins with "169.254," enter "ipconfig /release" on the command line, and tap the "Enter" key. Enter "ipconfig /renew" at the command line, and tap the "Enter" key. Then enter "ipconfig /all," and tap the "Enter" key. Inspect the command line output and verify that the network adapter IP address is no longer "0.0.0.0" or starting with "169.254." Then proceed to the next step. However, if the IP address did not change, enter "netsh int ipreset c:\resetlog.txt," and tap the "Enter" key. Then reboot the computer. Confirm that the network adapter IP address has changed, and then move to the next step.
Enter "ping gateway." Substitute "gateway" with the gateway IP address displayed in the "ipconfig /all" command line output in the previous step. Proceed to the next step if four replies are received. Otherwise, confirm the IP address on the private network side of the router, firewall or ISP is the same as the gateway IP address that was listed in the command line output. If the IP addresses do not match, configure the computer to use DHCP to obtain an IP address automatically and then execute the "ping gateway" command again, substituting the private network-side IP address of the router, firewall or ISP. Move to the next step if four replies are displayed in the command line output.
Enter "tracert remote_server" substituting the IP address of a remote server for "remote_ server." If the command line output completes by displaying the remote server IP address, then network connectivity is operational. Otherwise, if the command line output shows lines of "****" and no reply from the remote server, then the network device following the last device to reply should be inspected for operational issues and repaired to restore network connectivity.
- Note the location of any firewalls or proxy servers and configure them to forward ICMP echo requests prior to testing.
Dave Wilson has been writing technical articles since 1993, including manuals, instructional "how-to" tips and online publications with various websites. Wilson holds a Bachelor of Arts in psychology from the University of California, Los Angeles and has Microsoft, Cisco, and ISC2 (CISSP) technical certifications. He also has experience with a broad range of computer platforms, embedded systems, network appliances and Linux.