A
Dynamic Host Configuration Protocol (DHCP) server is a computer that has
Windows Server 2008 R2 installed on it, and is responsible for assigning IP
addresses to the computers automatically. IP addresses assigned to the
computers by DHCP server are known as dynamic IP addresses, and the computers
that are configured to obtain the IP addresses automatically from the DHCP
server are called DHCP client computers.
During
DHCP server configuration, administrators specify a range of IP addresses in
the DHCP scope. All IP addresses that fall within the specified range are
stored in IP Address Pool. Every time a DHCP client computer requests an IP
address from a DHCP server, the server randomly picks up any one of the
available IP addresses from its address pool and assigns it to the requesting
client computer. This process is known as dynamic IP address assignment.
Dynamic Host Configuration Protocol (DHCP) IP Address
Assignment Process
The
process of IP address assignment completes in four steps called DORA where D
represents DHCP Discover, O represents DHCP Offer, R represents DHCP Request
and A represents DHCP Acknowledge. Description of DORA is as below:
1.
DHCP Discover –
DHCP Discover is a broadcast packet that is sent from a DHCP client computer.
DHCP Discover packet is broadcasted to search for all available DHCP servers in
the network. Since it is a broadcast packet, it is received by all the
computers connected to the network (including all available DHCP servers)
without exceptions.
2.
DHCP Offer –
DHCP Offer is a unicast packet that is sent from the DHCP server to the
requesting DHCP client computer in response to the received broadcasted DHCP
Discover packet. DHCP Offer packet contains an available IP address from the
address pool, offering it to the requesting DHCP client computer.
3.
DHCP Request –
DHCP Request is a unicast packet sent from a DHCP client computer to a DHCP
server from which it has received DHCP Offer packet. DHCP client computer sends
DHCP Request packet requesting the DHCP server to assign the offered IP
address.
4.
DHCP Acknowledge –
DHCP Acknowledge is a unicast packet sent from the DHCP server to the DHCP
client computer confirming the successful assignment of the requested IP
address.
Prerequisites
for Installing DHCP Server Role
Before
DHCP server role is installed on a Windows Server 2008 R2 computer,
administrators must verify that:
·
The computer that is to be configured as
DHCP server has been assigned with a static IP address.
·
A DNS zone has been created on any
network operating system in the network if no domain controller is present.
Install and
Configure Dynamic Host Configuration Protocol (DHCP) on Windows Server 2008 R2
To install and configure Dynamic Host Configuration
Protocol (DHCP) on Windows Server 2008 R2, administrators must follow the steps
given as below:
1.
Log on to Windows Server 2008 R2
computer with the domain administrator or enterprise administrator account
credentials on which DHCP server is to be installed and configured.
2.
Make sure that the computer has been
assigned with a static IP address.
3.
Ensure that the DNS server is available
anywhere in the network and is properly configured.
4.
On the desktop screen, click Server
Manager icon from the taskbar.
5.
On the Server Manager window,
from the console tree in the left, make sure that Roles option
is selected.
6.
On the right pane, make sure that the Roles
Summary section is expanded.
7.
From the expanded section, click Add
Roles.
Click
Add Roles
8.
On Add Roles Wizard window,
click Next.
Check
DHCP Server Checkbox
10. On the DHCP Server page, click Next.
11. On Select Network Connection Bindings page,
make sure that the IP address representing the network connection that is to be
bound is checked from the Network Connectionslist.
Select
Network Connection
12. Click Next to continue.
13. On Specify IPv4 DNS Server Settings page,
populate the Preferred DNS serer IPv4 addressand optional Alternate
DNS server IPv4 address fields with the correct values.
14. Once specified, click Validate to
confirm the availability of DNS server and click Next.
15. On Specify IPv4 WINS Server Settings page,
leave everything as default and click Next.
16. On Add or Edit DHCP Scopes page,
click Add.
17. On Add Scope box, populate the Scope
name, Starting IP address, and Ending
IP addressfields with the desired values and click OK.
18. Back on Add or Edit DHCP Scope page,
click Next.
19. On Configure DHCPv6 Stateless Mode page,
leave everything as default and click Next.
20. On Specify IPv6 DNS Server Settings page,
leave everything as default (assuming that the network setup doesn’t have IPv6
addressing scheme) and click Next to proceed.
21. On Authorize DHCP Server page, make
sure that the Use current credentials radio button is
selected. Alternatively, Use alternate credentialsradio button can
also be selected to specify the domain admin credentials that is to be allowed
to authorize DHCP server in AD DS.
Authorize
DHCP
Note: Authorize DHCP Server page will be displayed only
when an
Active Directory Domain Controller is present in the network.
In case the Active Directory Domain Controller is absent, the page is
not displayed.
22. Click Next to proceed.
23. On Confirm Installation Selections page,
review the settings and click Install to start the DHCP
installation and configuration process.
24. Once installed, click Close on the Installation
Results page.
25. Close Server Manager window when
done.