This read-write object holds one of the IP addresses permitted to access the unit, with 0.0.0.0 meaning the entry is not defined. This is the actual whitelist entry enforced when cdm570AccessListEnforcement is turned on, so any managing station whose address isn't present in one of the four rows of this table will be denied SNMP access once enforcement is enabled -- making it essential to populate this correctly before flipping that enforcement switch. An admin adding a new backup NMS to the whitelist would set one of the unused rows, currently 0.0.0.0, to that address before that new station can successfully poll the modem with access-list enforcement active.