How to stop ip address conflicts with another laptop and wireless printer

[Guest]

Hello, I use a wireless laptop and a wireless printer with no problems until my lodger's friend comes and connects to the network. That is when I lose printer connection and sometimes get the IP address conflict message. Obviously something to do with his laptop wireless connection, but what? and how do I fix it?

 

[john-b691]

Either he is using a fixed IP which conflicts or you have fixed ip on your devices and your DHCP setting on the router do not exclude that address and gives it to him.