To restrict to particular MAC addresses,
the Cisco manual says menu select:
DHCP > IP & MAC Binding.
and enter 0.0.0.0 for the Static address,
Problem Cisco system does not accept 0.0.0.0.
Nor can we leave the Static IP field blank.
the data entry field is highlighted, and an error X is displayed on the corner of that field.
Cisco pop-up error message (in red)
Static IP Address last value is out of range! [1~254]
Cisco manual>> Enter the known static IP address of the device in the Static IPv4 Address field. If the device does not have any static IP address and obtains the IP address dynamically from a DHCP server, enter 0.0.0.0 to bind the MAC address of the device with the IP address assigned by the DHCP server.
Using Cisco to DHCP serve so since we do not know the IP addresses in advance.
(Nor do we care which IP address is DHCP assigned.)
https://www.cisco.com/c/en/us/support/docs/smb/routers/cisco-rv-series-small-business-routers/smb4226-manage-ip-and-mac-binding-on-rv320-and-rv325-vpn-routers.html
RV325
current firmware v1.5.1.13 (2020-10-27)
