If auto disconnect doesn’t work, go to the advanced options of your dial up settings: in Internet Explorer, go to Tools > Internet options > Connections > Dial-up settings > Advanced dial-up settings, and turn on the option to “disconnect if connection no longer required.”
If that doesn’t work, open the Registry Editor, and navigate to HKEY_CURRENT_USER\RemoteAccess\Profile\<Connection> Now look at the following DWORDS: EnableExitDisconnect EnableAutodisconnect If either one has the data of 00 00 00 00, right-click the value and select Modify. Change the data to 01 00 00 00. Also check this registry key: HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings. Look at the DWORD: EnableAutodisconnect. If this value has the data of 00 00 00 00, change it to 01 00 00 00. Reboot your computer.