Capping bandwidth
Drag a device's slider to set its ceiling in MB/s. The change applies within milliseconds, with no restart on either machine. Upload and download are capped independently.
A cap is usually the better tool than a block. Most complaints that lead people to remove a device are really about one machine saturating the connection, and a limit fixes the congestion without anyone losing access.
Blocking a device
The Online toggle cuts a device off entirely. It stays associated to Wi-Fi but its traffic stops passing. Flip it back to restore access immediately.
Cut everyone except me
Blocks every discovered device except the machine you are on. Useful when you need the whole connection for a call or a large transfer. Restore all reverses it.
Policies persist
Caps, blocks and custom names are keyed to each device's MAC address and written to devicepolicy.txt beside the executable. They survive closing the app, restarting Windows, a crash, and a device getting a new IP from DHCP.
MAC keying matters: a phone that sleeps for an hour and returns on a different IP keeps its limit, which IP-based tools cannot do.
The app must stay running
Enforcement happens live on the network, so limits only apply while Perimetery PRO is running. Close it and the network returns to normal immediately. It is not a permanent router configuration change.