Hardware manual

44 Chapter 2 Inside Mac OS X Server
Network Services
Mac OS X Server helps you manage network communications by providing:
 Dynamic Host Configuration Protocol (DHCP) service
 Domain Name System (DNS) service
 Firewall service
 Network Address Translation (NAT) service
 Virtual Private Network (VPN) service
 Network time service
 Gateway Setup Assistant
 IP failover
The network services administration guide provides information about network
services.
DHCP
DHCP is especially useful when an organization has more clients than IP addresses.
IP addresses are assigned on an as-needed basis, and when they’re not needed they’re
available for use by other clients.
DHCP helps you administer and distribute IP addresses dynamically to client computers
from your server. From a block of IP addresses that you define, your server locates an
unused address and “leases” it to client computers as needed. The server’s DHCP service
also supports static IP address assignment to computers with a specific Ethernet (MAC)
address.
As you learned in “Search Policies” on page 31, you can automate the directory services
setup of Mac OS X clients using your DHCP server’s Option 95 support. This option lets
client computers learn about their directory settings from a DHCP server.
DNS
DNS service lets users connect to a network resource, such as a web or file server, by
specifying a name (such as server.example.com) rather than an IP address (such
as192.168.11.12). DNS is a distributed database that maps IP addresses to domain names.
A server that provides DNS service keeps a list of names and the IP addresses
associated with the names. When a computer needs to find the IP address for a name,
it sends a message to the DNS server (also known as a name server). The name server
looks up the IP address and sends it back to the computer. If the name server doesn’t
have the IP address locally, it sends messages to other name servers on the Internet
until the IP address is found.