How can I tell if someone is on my WiFi?
A public IP lookup will not name the extra phone on your network. Check the router device list, change the WiFi password, and know that hide my IP with a VPN will not kick a neighbor off.
Yes, sometimes. If the WiFi is slow, new names appear in the router list, or your public IP shows traffic you do not recognize, someone else may be on the network. A public IP address is shared by everyone behind that router, so IP lookup will not name the extra phone. The router’s client list will.
How can I see devices on my WiFi?
Log into the router. The address is often on a sticker, or listed as the gateway in your computer’s network settings. Open the connected devices or DHCP client page. Names can lie. A “iPhone” you do not own is a clue. A mystery MAC address is a clue.
What should I do if a stranger is on my WiFi?
Change the WiFi password. Use WPA3 if you can, otherwise WPA2 AES. Turn WPS off. Kick unknown clients if the router has a button for that. Guest WiFi is for visitors so they never see printers and laptops.
Then check the admin password on the router itself. If it was still admin or printed for the building, change it. Remote administration from the internet should be off.
Will changing my IP remove them?
No. Power cycling for a new dynamic IP does not kick a device that knows the WiFi password. Hide my IP with a VPN also does not. The guest is local. Fix the password and the router.
Does a busy public IP mean I am hacked?
Not by itself. Streaming, backups, and phones chew bandwidth. CGNAT can make your mobile IP look “busy” with strangers you will never meet. For home WiFi, trust the router list more than an IP geolocation map.
Keep the firmware updated. A default password is how neighbors and scripts walk in.