Naming Services: A Quick Comparison

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