Yes, that change almost certainly requires rebooting for it to take effect (as do most system-level changes).
If you simply cannot reboot at the moment, but still want to force the change, you can attempt to restart the appropriate services and drivers, however that may be difficult or even impossible due to dependencies and restrictions.
If you want to try it (be wary that you might end up crashing the system by doing so, which would put you right back at rebooting), you can use the Device Manager:
- Open the Device Manager (Start ⇨
- Enable hidden devices (View ⇨ Show hidden devices)
- Expand the Non-Plug and Play Drivers branch
- Open the Properties dialog for TCP/IP Protocol Driver
- Select the Driver tab and click
- If you have no dependent services/drivers running, then it should stop and you can click
[Start] to restart it
- If you have dependent services/drivers running, it will prompt you to stop them (which may have other services/driver dependent on those)
If you restarted the TCP/IP Protocol Driver, then the service should be using the new settings, but there may still be other services/drivers that access that parameter, so you may still end up having to reboot (also, you can try disabling the network adapter under Control Panel ⇨ Networking to get it to propagate to the NIC’s driver).