Troubleshooting Network Problems

Are you having network connectivity problems? You are unable to connect to another computer, to the Internet or to shared resources within an organization! Then this article will guide you through the basic tools available in Windows 7 and the steps you need to take when troubleshooting network connectivity problems.

I suggest that you start with simple things first and gradually move on to tools that require some knowledge and time to execute. Every problem may be the consequence of some events and hence, it is logical to verify the particular area where the events have happened! For example, if you are experiencing network connectivity issues after installing a new network switch then most probably the problem lies within the switch itself or an unplugged network cable. Assuming a generic fault finding exercise, I suggest you perform the following steps:

  1. Start with the most obvious stuff. Ensure that no cables have been pulled out or are halfway out. With computers and network switches turned on check that the LEDs (Light Emitting Diodes) on the both the network interface card at the back of computer and on the network switch are lit or show some activity. Then make sure that the devices or other computers you are trying to connect to are all switched on and wired correctly.
  2. If your setup is wireless-based, then try restarting the wireless access device that provides network and Internet connections. You may need to restart your computer if the WAP (Wireless Access Point) is configured as a DHCP server. If you’re having just Internet connectivity issues then restart the modem provided by your ISP. Modems may go faulty hence, check that the indicators (LEDs) are lit according to your ISP instructions.  If your setup uses ICS make sure that it is properly configured and that no WAP device has been added afterwards and is conflicting with the computer running ICS. 
  3. Check that you can load the network interface card configuration page as to verify that it is installed without any glitches. Sometimes disabling and enabling the network interface card from the Network Connections window may solve the problem. If you are unable to load the network interface card properties (Local Area Connection properties window) or having problems disabling and enabling it then the device driver might be corrupt or needs updating. For more details about Windows 7 Device Manager go here and for Device Drivers Options go here.
    Windows 7 computers need to have Network Discovery enabled in order to be able to see each other. Network discovery is a network setting that affects whether your computer can find other computers and devices on the network and whether other computers on the network can find your computer. By default Network Discovery is enabled but I suggest that you check this setting by clicking Change Advanced Sharing Settings in the Network and Sharing Center.
  4. Having reached this step, it means that you need to perform some advanced tasks now. Start by verifying that the network interface card or adapter is configured according to your setup. That is, either set to get the IP configuration dynamically (dhcp) or you need to set all the details (static IP configuration). See Configuring the lan interface for assistance. The most basic tools found in Windows 7 are the ping and ipconfig command line utilities. For more details about these tools visit Troubleshooting IP configuration, however, if you are not familiar with these tools you can use the Network Diagnostics Tool. For more details go here.
  5. Windows Firewall is enabled by default and if you are using the ping command to test network connectivity as explain in the previous step then you need to set a firewall rule that allows ICMP echo requests. You access Windows firewall by clicking System and Security in Control Panel and then clicking Windows Firewall. You can turn the firewall off during troubleshooting by clicking Turn Windows Firewall on or off on the left hand side of the Control Panel\System and Security\Windows Firewall window. If you decide to leave the firewall on and just enable a rule for ICMP packets, I find it more practical to add an allow rule using the netsh command line tool rather than adding rules from the GUI. From an elevated command prompt type in:
    netsh advfirewall firewall add rule name=”ICMPv4″ protocol=icmpv4:any,any dir=in action=allow

    You can verify that the rule was added successfully by clicking Allow a program or feature through Windows Firewall from the Control Panel\System and Security\Windows Firewall window and see that an entry with the name ICMPv4 is added to the list of allowed programs. To disable the rule, from an elevated command prompt type:
    netsh advfirewall firewall delete rule name=”ICMPv4″ protocol=icmpv4:any,any

Happy Troubleshooting :)