This holds the first of up to four IP addresses in the modem's management access control list, restricting which hosts may reach the modem's Web, Telnet, or SNMP management interfaces. Only traffic from addresses actually populated in this access list, once cdmipAccessListEnforcement is turned on, is allowed to manage the modem, so this is the first entry an admin fills in, typically with the primary NMS or admin workstation's address. Setting this to 10.20.1.5 would allow only that host, plus whatever is in slots 2 through 4, to open a management session to the modem once enforcement is enabled.