If you would like to see who (or what) is tapped into your wireless network, you can take a peek with router utilities and mobile apps...
Depending on your interest in technical fiddling, you can see what other devices are connected to your network in several ways. For one, you could log into your wireless router’s administrative page and check its DCHP Client Table (sometimes called the DHCP Client List or Attached Devices, as some router companies use different terms) to see the roster of computers, smartphones, tablets and other gear currently connected to the wireless router...
If that sort of thing seems like way too much work, you can also get a program or app that scans your network for connected devices. Your router maker may have its own app, like Netgear’s Genie, Linkys Connect or Apple’s AirPort Utility for iOS.
You can also find software from other developers that is designed to reveal the devices connected to your wireless network. NirSoft Wireless Network Watcher. Who’s on my WiFi for Windows and the Fing network scanner for Android and iOS are among the options. more