A security level which applies to this workgroup as a whole. Security applies in conjunction with the range table below, which locks hosts to interfaces and/or physical address. Packets are filtered out if security is violated.

For a high (4) security workgroup, a host must reside on the interface and with the physical address configured in a range table entry. For medium (3) security a host must reside on a configured interface, but unless a physical address is also specified in that range entry, the physical address is not constrained. For low (2) security a host is free to reside on any interface with any physical address if not configured in the range table, but if configured must match a configured entry. If security is none (1) the range table does not apply.