29 August 2008

First Steps in Home Network Troubleshooting

When you realized there's something wrong with your home network, you need to do first steps of troubleshooting using this tool I show on the left picture.

Isn't that windows command prompt? you bet it is, you don't need some kick ass software just to find out your home network problems.
I usually jump right to command prompt to find out what happen on my network.

Step One:
You need to type in this command at the command prompt:


What this does is pinging your own network card, if you get reply then there's nothing wrong with it, if no reply this means there's a problem with your TCP/IP stack.
There is a question related to TCP/IP stack in the CCNA exam.
You can use the following commands to reset your TCP/IP stack:

netsh int ip reset resetlog.txt

netsh winsock reset catalog

Step Two:
No problem with your TCP/IP stack but still no connection, try pinging other devices in the network.
Say you know your router has IP address of then type the following:


If there's replies then you know there's no problem within your internal network, if not type the following to find out whether you got IP from the router if you use DHCP:

ipconfig /all

If you don't get IP from the router do the following to renew your IP

ipconfig /release

ipconfig /renew

Step Three:
Hmmm... you can connect to other devices in your network but can't get to the internet. Try to ping google using:

ping google.com

If you find no replies, try to ping using IP address of external site, for example I know that google.com has IP address then I ping it:


If it works out then there's a problem with your ISP's DNS servers, try to contact your ISP about this.
If you still can't get to the internet, try turn off all the devices in your network for about 10 minutes and turn them on again using the following order:

Modem - Router - Switch - Your computer

You need also check your firewall settings, the easy way but not recommended is to shut down your firewall just for a moment and try connecting to the internet while the firewall down. This is to find out if your firewall is blocking your access to the internet.

Now the above steps are only the first steps you need to take if you have problem with your network, there are way too much problems that can happen in a network but you can use these steps for your guidelines in troubleshooting network.