I have come accross several cases of a corrupted or missing tcpip.sys file in the past few weeks, possibly the result of a failed windows update or third party software install.

While easy to repair, this problem can have massive impacts on a system, virtually severing all levels of network connectivity.

Symptoms

• "unable to query host name" being generated when issuing the ipconfig command
• The network status constantly showed "Network cable unplugged"
• Could not start the ICS service
• Using the LAN repair function resulted in Failed to query tcp/ip settings for the connection. Cannot proceed
• LAN Support tab contained no data at all.

Fix / Solution

After a period of troubleshooting we noticed that tcpip.sys was missing from our Windows\System32\drivers folder. Once we had identified this we were quickly able to source a copy of the file tcpip.sys and copy it into the above directy.

Once the computer is restarted it should regain all network connectivity.

We have attached a copy of tcpip.sys should you need to replace yours.

NOTE: Attached file (tcpip.sys) is for windows XP only.