An apparatus (120, 130, 140), disposed in a subnet, comprising: a Network Communication Interface, NCI, configured to enable the apparatus (120, 130, 140) to communicate with other apparatuses in the subnet; a storage medium, configured to store a configuration file associated with the apparatus (120, 130, 140), wherein the configuration file comprises a plurality of first Internet Protocol, IP, addresses, each of which corresponds to a respective one of the apparatus (120, 130, 140) and other apparatuses in the subnet; and a controller, coupled to the storage medium and the NCI, and configured to perform the following: sending a Dynamic Host Configuration Protocol, DHCP, discover message to a DHCP server in the subnet via the NCI; receiving a DHCP offer message indicating a second IP address of the DHCP server and a predetermined Internet Protocol, IP, mask from the DHCP server via the NCI in response to sending the DHCP discover message; modifying the first IP addresses in the configuration file based on the second IP address and the predetermined IP mask, by determining a portion of each of the first IP addresses based on the predetermined IP mask and replacing the portion of each of the first IP addresses with the corresponding portion of the second IP address; and using the modified first IP addresses to configure IP addresses of the apparatus (120, 130, 140) and other apparatuses in the subnet via the NCI. a Network Communication Interface, NCI, configured to enable the apparatus (120, 130, 140) to communicate with other apparatuses in the subnet; a storage medium, configured to store a configuration file associated with the apparatus (120, 130, 140), wherein the configuration file comprises a plurality of first Internet Protocol, IP, addresses, each of which corresponds to a respective one of the apparatus (120, 130, 140) and other apparatuses in the subnet; and a controller, coupled to the storage medium and the NCI, and configured to perform the following: sending a Dynamic Host Configuration Protocol, DHCP, discover message to a DHCP server in the subnet via the NCI; receiving a DHCP offer message indicating a second IP address of the DHCP server and a predetermined Internet Protocol, IP, mask from the DHCP server via the NCI in response to sending the DHCP discover message; modifying the first IP addresses in the configuration file based on the second IP address and the predetermined IP mask, by determining a portion of each of the first IP addresses based on the predetermined IP mask and replacing the portion of each of the first IP addresses with the corresponding portion of the second IP address; and using the modified first IP addresses to configure IP addresses of the apparatus (120, 130, 140) and other apparatuses in the subnet via the NCI. sending a Dynamic Host Configuration Protocol, DHCP, discover message to a DHCP server in the subnet via the NCI; receiving a DHCP offer message indicating a second IP address of the DHCP server and a predetermined Internet Protocol, IP, mask from the DHCP server via the NCI in response to sending the DHCP discover message; modifying the first IP addresses in the configuration file based on the second IP address and the predetermined IP mask, by determining a portion of each of the first IP addresses based on the predetermined IP mask and replacing the portion of each of the first IP addresses with the corresponding portion of the second IP address; and using the modified first IP addresses to configure IP addresses of the apparatus (120, 130, 140) and other apparatuses in the subnet via the NCI.