Updated: February 23, 2009
Computers on your network use TCP/IP to communicate with each other. This protocol requires that each network interface in your environment has an IP address (for example, 10.141.169.232). There are two ways a network device can get an IP address assigned to it:
It can have an address permanently assigned to it (static addressing).
It can have a DHCP server assign it an address (dynamic addressing).
When a computer has an IP address that is assigned from a DHCP server, it is said to have a “lease” on that address. When that lease expires, the computer contacts the DHCP server again to renew the lease. The DHCP server uses a database to track which computers have leased addresses.
Using a DHCP server for dynamic addressing has many advantages over static addressing:
You can manage settings centrally (such as which DNS server to use for a group of computers) instead of editing those settings on each computer.
You can avoid IP address conflicts (when two network interfaces have the same IP address).
You can still assign static addresses by using a reservation. This maps the network interface’s unique MAC address to a specific IP address on the DHCP server.
Your desktops and network devices can automatically register with DNS through dynamic updates.
It is recommended that you use the DHCP Server service to assign IP addresses and other network settings to your clients. However, servers should be statically addressed. This includes domain controllers and servers that are running Exchange Server or Windows EBS.
When the DHCP Server service runs on a domain controller, the DHCP Server service must be authorized in Active Directory Domain Services to give out IP addresses. Unauthorized DHCP Server services do not give out IP addresses. You can authorize a DHCP server from the DHCP console.
Background information specific to Windows Essential Business Server
During installation, Windows EBS automatically installs the DHCP server role on the Management Server if no DHCP Server service is detected in the environment. In this case the DHCP server role is configured, a scope is created with the settings that you entered, the scope is authorized, and the service is started. If an existing DHCP Server service is detected, you are given the choice to configure and start the DHCP Server service.