Steps for Troubleshooting a Home Network

My sister had a few questions about how one might troubleshoot a residential router. Figure I'd post here for anyone else who might find the steps helpful as well.

First off, be sure the trouble isn't with your browser. Make sure network connection settings (web proxy, VPN) in browser preferences are correct. Reset to default settings if necessary. For the purposes of troubleshooting, the best approach for testing connectivity would be to use the "ping" command from the command prompt.

1. Check the IP address of the computer used to connect to the router
• If address begins with 192.168.*.*, proceed to step 2
• If address begins with 169.254.*.*, proceed to step 5
2. Power cycle the router and the modem.
• Steps to power cycle: pull power supply plug from outlet, wait 1min, return plug to outlet.
• Check status lights for both the router and the modem.
• Power cycling the router clears memory and hard boots the system with a fresh session. Most routers also have the option to reboot the system using the system's administrative software—accessed from a browser with the router's IP address (http://192.168.0.1). If status lights do not eventually show the modem to be connected to the internet, check the cable modem.
• Power cycling the modem forces it to reestablish a connection with the ISP. If status lights do not eventually show the modem to be connected to the internet and active, contact your ISP for support.
3. Check the router setup.
• Open a browser window and connect to the router at http://192.168.0.1, sign in using the administrative user name (admin) and password.
• If the password is forgotten, press and hold down the reset button found on the router for 5 to 10 seconds to reset to factory default settings.
• Log in to the system using the factory default password (admin, password, motorola, etc.) found in the user guide for the device.
• Reset passwords (admin and wireless access), reconfigure wireless security and any firewall settings that may have been set.
• Check the IP address and gateway information for the router. Make sure the router has obtained an IP address from the modem, and has populated DNS server addresses from the modem. If not, release and renew the IP address. Takes a few seconds. May need to refresh the window to view the new address.
• If still no IP address, check modem status lights. May need to power cycle again.
4. If using wireless, remove the preferred network from Wireless Network Connection Properties and reconnect.
• Go to Start > Control Panel > Network Connections.
• Right click Wireless Network Connection, select Properties, select the Wireless Networks tab.
• Remove all networks under Preferred Networks: select a network, then select Remove.
• After all saved networks have been removed, select OK to close the window.
• From the Network Connections window: right click Wireless Network Connection, select View Available Wireless Networks.
• Select the wireless network setup with the router, and select Connect. Enter the password when prompted.
5. Restart the computer to begin fresh. After loading the OS, recheck the IP address of the computer. If address begins with 169.254.*.*:
• Release the IP address, flush the DNS, renew the IP address.
• Go to Start > Run. Type "cmd" and select OK.
• From the command prompt, type "ipconfig /release *" and press the Enter key.
• Type, "ipconfig /flushdns" and press Enter.
• Type, "ipconfig /renew" and press Enter.
• Type, "ipconfig /all" to check IP address, DNS, and gateway information.
• If IP address is still 169.254.*.*, proceed to the next step.
• Re-install network device drivers.
• Go to Start, right click on My Computer, select Properties > Hardware > Device Manager.
• Expand the Network Adapters section.
• Find the problem adapter, select it and press the Delete key to remove the device.
• If the device is not found, look for devices with a yellow question mark for an icon. Device drivers may not have been installed properly in the first place.
• If the network device has a yellow question mark for an icon, select it and press the Delete key.
• Select Network Adapters. From the menu, select Action > Scan for hardware changes.
• Follow instructions for installing drivers for devices found. May need to use a second computer to download the latest drivers.

Also, when using wired connections, be sure to check the cables. Sometimes the answer is as simple as replacing a damaged cable. Keep in mind, damage isn't always visible from the outside.

And use whatever resources you have at hand. Try different configurations, such as connecting the modem directly to the computer in order to remove the router from the equation and narrow the issue to the modem or the computer. However, the modem must be powered down before switching it over to a different device. The modem is only able to serve one specific device at a time, and retains the hardware address of that device in memory. Powering the modem down will clear memory and allow for a different device to be connected.

Finally, check to make sure network cards are firmly seated inside the computer, and that all cables are securely connected.