The Process of Troubleshooting Network Problems

To most users, the term connectivity problems describes a wide range of problems, including a failed network connection, an application that cannot connect because of firewall filtering, and serious performance problems. Therefore, the first step in troubleshooting connectivity problems is to identify the scope of the connectivity problem.

To identify the source of a connectivity problem, follow these steps and answer the questions until you are directed to a different section:

1. Open the Network And Sharing Center by clicking the network icon in the system tray and then clicking Open Network And Sharing Center. At the bottom of the page, click Troubleshoot Problems and follow the prompts that appear. If Windows Network Diagnostics does not identify or resolve the problem, please choose to send the information to Microsoft to help improve Windows Network Diagnostics. Then, continue following these steps.
2. Are you attempting to connect to a wireless network, but your connection attempt is rejected? If so, see the section titled "How to Troubleshoot Wireless Networks" later in this tutorial.
3. Are you attempting to connect to a remote network using a VPN connection, but your connection attempt is rejected?.
4. Can you occasionally access the network resource, but it is unreliable or slow? If so, see the section titled "How to Troubleshoot Performance Problems and Intermittent Connectivity Issues" later in this tutorial.
5. Can you access other network resources using different applications, such as e-mail or different Web sites? If not, you have a network connectivity problem or a name resolution problem. If you can contact servers using the IP address instead of the host name, see the section titled "How to Troubleshoot Name Resolution Problems" later in this tutorial. If servers are not accessible when you specify an IP address or if you do not know an IP address, see the next section, "How to Troubleshoot Network Connectivity Problems."
6. Are you trying to join a domain or log on to your computer using a domain account but are receiving an error message that the domain controller is unavailable? If so, see the section titled "How to Troubleshoot Joining or Logging on to a Domain" later in this tutorial.
7. Open a command prompt and run the command Nslookup servername. If Nslookup does not display an answer similar to the following, you have a name resolution problem. See the section titled "How to Troubleshoot Name Resolution Problems" later in this tutorial for information on solving these problems.
   C:\>nslookup yahoo.com
8. Are you trying to connect to a shared folder? If so, see the section titled "How to Troubleshoot File and Printer Sharing" later in this tutorial.
9. If other network applications work and name resolution succeeds, you might have a firewall problem. See the section titled "How to Troubleshoot Application Connectivity Problems" later in this tutorial.