Sometimes udhcpd 1.19.4-vd linux vdlinux.3.1.1. Conects to my Wi-Fi and i think someone is stealing Wi-Fi?

Sometimes "udhcpd 1.19.4-vd linux vdlinux.3.1.1." conects to my Wi-Fi and i think someone is stealing my Wi-Fi because moments after it connects "johoseps iphone" conects and i would like to block him because my Wi-Fi stops working, i'm a pretty advanced user but i don't know how to really stop him from connecting to my Wi-Fi ever again.

I've been searching what it is online and i can't really figure it out what it is, so i would also like to know exactly what it is, i've understud id had to do with servers.

Within the router settings, Change the password. If that doesn't work, block the mac address that is connecting.

Are you sure its not your actual router? What IP does it get?

First, turn off any WPS on your router, if you have it. That may be how they are cracking your Wi-Fi password, since WPS is not secure, just like WEP Wi-Fi security (can be cracked in 5 minutes). Then, make sure you have WPA2 Wi-Fi security and set a long Wi-Fi password that is at least 9 characters long and contains special characters or numbers in it.
I guarantee at that point on, no one will be stealing your Wi-Fi. Only those that know your Wi-Fi password will be able to connect.

New Wifi camera? :-]