Question How can i tell if I'm being kicked off my modem?

[que7i]

I live in an apartment, from time to time we can't log in and using ethernet doesn't work either, but 1 guy can always use it, a factory reset fixes this every time, but, sometimes, this fix lasts little when he is awake (right now he is asleep). I figured out that how to choose wich devices can use the wifi (MAC filtering) and how to disable ethernet only with the ip address and the modem password, it's easy so I believe he could do it aswell.

 

[kanewolf]

I live in an apartment, from time to time we can't log in and using ethernet doesn't work either, but 1 guy can always use it, a factory reset fixes this every time, but, sometimes, this fix lasts little when he is awake (right now he is asleep). I figured out that how to choose wich devices can use the wifi (MAC filtering) and how to disable ethernet only with the ip address and the modem password, it's easy so I believe he could do it aswell.

He is probably doing something like ARP spoofing -- https://en.wikipedia.org/wiki/ARP_spoofing where he is running software that makes other devices think his PC is the router and therefore blocks other users. There are articles on how to detect this situation -- https://www.comparitech.com/blog/information-security/arp-poisoning-spoofing-detect-prevent/