Server, Clients, and Relay Agents

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Server, Clients, and Relay Agents
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bet | 5/9 | Sana | 26.03.2020 | Hajmi | 353,5 Kb. | | #8841 |
Server, Clients, and Relay Agents
Three basic components make up DHCP in Windows Server 2003:
DHCP Servers
DHCP Clients
DHCP/BOOTP Relay Agents
DHCP Servers
The Microsoft DHCP Server service includes the DHCP snap-in, which is an easy-to-use graphical user interface management tool that allows network administrators to define DHCP client configurations. The DHCP server also includes a database for managing assignment of IP addresses and other configuration parameters.
As listed in Appendix A, the DHCP Server service supports more than 30 DHCP options, which are defined by the RFC 2132. The DHCP server can assign the following TCP/IP configuration parameters:
IP addresses for each network adapter in a client computer.
Subnet masks to identify the IP network portion from the host portion of the IP address.
Default gateways (routers), which connect a single network segment to others segments.
Additional configuration parameters, optionally assigned to DHCP clients (such as IP addresses for DNS or WINS servers that a client might use).
One or more computers on a network must run Windows Server 2003 with TCP/IP and DHCP installed to provide clients with dynamic IP addresses. After installing the DHCP Server service on a computer running Windows Server 2003, and creating and activating scopes, the server automatically creates a DHCP server database.
DHCP Clients
Many low-cost industry standard platforms can act as DHCP clients, as defined in RFC 2132.
The four steps required for a DHCP client to acquire a lease from a DHCP server initiate automatically when the computer starts. Computers running the following Microsoft operating systems can act as DHCP clients:
Windows Server 2003
Windows XP
Windows 2000 Server
Windows 2000 Professional
Windows NT Workstation 4.0 and earlier
Windows NT Server 4.0 and earlier
Windows Millennium Edition
Windows 98
Windows 95
Windows for Workgroups version 3.11 (with the Microsoft 32-bit TCP/IP VxD installed)
In addition to supplying configuration information through DHCP, network administrators can also override dynamic settings with manual ones. Any information that is manually entered into a client's TCP/IP configuration overrides dynamic settings.
DHCP BOOTP Relay Agent
BOOTP and DHCP rely on network broadcasts to perform their work. Routers in normal routed environments do not automatically forward broadcasts from one interface to another. A relay agent must forward these messages. A router or a host computer configured to listen for DHCP BOOTP broadcast messages and direct them to a specific server running DHCP can act as a DHCP relay agent. Using relay agents eliminates the necessity of having a server running DHCP on each physical network segment. Relay agents direct local DHCP client requests to remote DHCP servers and also return remote DHCP server responses to the DHCP clients.
Windows Server 2003 includes a DHCP relay agent routing protocol component with the Routing and Remote Access service. A DHCP relay agent service also comes with Windows Server 2003. Figure 3 shows three common designs.
Figure 3. Three DHCP Configurations Showing the Use of the DHCP BOOTP Relay Agent
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