Disabling DHCP on the Router
If you want to manually configure every client, you can disable the router from handing out and managing the addresses automatically. Bring up your router's web-based configuration utility by typing in its IP address; for example 192.168.0.1 or 192.168.1.1.
Log in and find the section where you can change the DHCP settings, such as on the General, Network, or DHCP tab. Once you find the DHCP settings, there should be a checkbox or option to enable/disable the server (see Figure 5).
Uncheck the appropriate option and save the settings. Then from now on, users won't be able to access the network or Internet until they've configured a static IP on their computer.