Naming Services: A Quick Comparison

	DNS	NIS	NIS+	LDAP
NAMESPACE	Hierarchical	Flat	Hierarchical	Hierarchical
DATA STORAGE	Files/ resource records	2 column maps	Multi-columned tables	Directories [varied]
SERVER NAMES	Master/slave	Master/slave	Root master/non-root master primary/secondary cache/stub	Master/replica
SECURITY	None	None (root or nothing)	Secure RPC (AUTH_DH) Authentication	SSL, varied
TRANSPORT	TCP/IP	RPC	RPC	TCP/IP
SCALE	Global	LAN	LAN	Global