Answer Description
Dynamic Host Configuration Protocol (DHCP) assigns IP's to network devices. Domain Name Service (DNS) translates between IP Addresses and Domain names. Address Resolution Protocol translates between IP Addresses and MAC Addresses (Reverse-ARP, RARP does the opposite)
Wikipedia
The Dynamic Host Configuration Protocol (DHCP) is a network management protocol used on Internet Protocol networks whereby a DHCP server dynamically assigns an IP address and other network configuration parameters to each device on a network so they can communicate with other IP networks A DHCP server enables computers to request IP addresses and networking parameters automatically from the Internet service provider (ISP), reducing the need for a network administrator or a user to manually assign IP addresses to all network devices In the absence of a DHCP server, a computer or other device on the network needs to be manually assigned an IP address, or to assign itself an APIPA address, which will not enable it to communicate outside its local subnet
Dynamic_Host_Configuration_Protocol - Wikipedia, the free encyclopedia