This value caps how many DHCP clients (identified via their learned bindings) are allowed on a specific untrusted port, defaulting to 2048 but configurable from 0 up to that maximum. Administrators lower this limit on access ports to prevent a single port from being flooded with excessive DHCP requests, which could indicate an attack or a misbehaving device. For example, an admin might set this to a small number like 5 on a port serving a single desk with only one or two expected devices, to limit how many DHCP clients can be learned there.