Windows 7: How to Determine the MTU Size

1. Open the 'Start' menu and type 'cmd' in the search field at the bottom. Wait for the icon 'cmd' or 'cmd.exe' to appear on the result list.
2. Right-click the 'cmd' or 'cmd.exe' icon, then click 'Run as Administrator' to open a Command Prompt window with administrative privileges. If you are logged in with a limited Windows account, you must supply an administrator's password to continue.
3. Type 'netsh interface ipv4 show subinterfaces' in the Command Prompt window and press 'Enter.'
4. Examine the value in the 'MTU' column next to your computer's Internet connection -- such as 'Local Area Connection' or 'Wireless Network Connection' -- to determine your current MTU value.