DHCP Installation

Dynamic Host Configuration Protocol

DHCP stands for "Dynamic Host Configuration Protocol".DHCP's purpose is to enable individual computers on an IP network to extract their configurations from a server (the 'DHCP server') or servers, in particular, servers that have no exact information about the individual computers until they request the information. The overall purpose of this is to reduce the work necessary to administer a large IP network. The most significant piece of information distributed in this manner is the IP address. It was created by the Dynamic Host Configuration Working Group of the Internet Engineering Task Force (IETF; a volunteer organization which defines protocols for use on the Internet). As such, it's definition is recorded in an Internet RFC and the Internet Activities Board (IAB) is asserting its status as to Internet Standardization. DHCP is an Internet Draft Standard Protocol and is Elective. BOOTP is an Internet Draft Standard Protocol and is Recommended.

DHCP is based on BOOTP and maintains some backward compatibility. The main difference is that BOOTP was designed for manual pre-configuration of the host information in a server database, while DHCP allows for dynamic allocation of network addresses and configurations to newly attached hosts. Additionally, DHCP allows for recovery and reallocation of network addresses through a leasing mechanism.

RARP is a protocol used by Sun and other vendors that allows a computer to find out its own IP number, which is one of the protocol parameters typically passed to the client system by DHCP or BOOTP. RARP doesn't support other parameters and using it, a server can only serve a single LAN. DHCP and BOOTP are designed so they can be routed.

When a DHCP-configured client (a computer or any other network-aware device) connects to a network, the DHCP client sends a broadcast query requesting necessary information from a DHCP server. The DHCP server manages a pool of IP addresses and information about client configuration parameters such as default gateway, domain name, the DNS servers, other servers such as time servers, and so forth. On receiving a valid request, the server assigns the computer an IP address, a lease (length of time the allocation is valid), and other IP configuration parameters, such as the subnet mask and the default gateway. The query is typically initiated immediately after booting, and must complete before the client can initiate IP-based communication with other hosts.

Depending on implementation, the DHCP server may have three methods of allocating IP-addresses.

• dynamic allocation: A network administrator assigns a range of IP addresses to DHCP, and each client computer on the LAN has its IP software configured to request an IP address from the DHCP server during network initialization. The request-and-grant process uses a lease concept with a controllable time periods, allowing the DHCP server to reclaim (and then reallocate) IP addresses that are not renewed (dynamic re-use of IP addresses).
• automatic allocation: The DHCP server permanently assigns a free IP address to a requesting client from the range defined by the administrator. This is like dynamic allocation, but the DHCP server keeps a table of past IP address assignments, so that it can preferentially assign to a client the same IP address that the client previously had.
• static allocation: The DHCP server allocates an IP address based on a table with MAC address/IP address pairs, which are manually filled in (perhaps by a network administrator). Only requesting clients with a MAC address listed in this table will be allocated an IP address. This feature (which is not supported by all routers) is variously called Static DHCP Assignment (by DD-WRT), fixed-address (by the dhcpd documentation), DHCP reservation or Static DHCP (by Cisco/Linksys), and IP reservation or MAC/IP binding (by various other router manufacturers).

 

Steps To Install DHCP

 

 

 

1. This option mainly depends upon your requirements whether you want to give static ip-address to each and every client within you network or you want the client computers to receive ip-address dynamically distributed by the DHCP server.
2. There is no compulsion to go for DHCP configuration options but in order to maintain flexibility at Intranet Level(LAN) I am giving the exact picture of what is required.
3. Click on Start--> Programs-->Administrative Tools-->DHCP.

 

 

 

 

 

2. DHCP console will open in front of you.

 

 

 

 

 

 

3. Here you can click on Action-->Add Server (in case if the default server is not added during Active Directory Installation)

 

 

 

 

 

4. In the above Image you will see that default server was added during Active Directory Installation and it is prompting for “Add a Scope” , hence we have to add a scope as-per our requirements

 

 

 

 

 

5. Right Click on sysbbsr-->New Scope(sysbbsr is an example,you can name it according to your needs)

 

 

 

6. Welcome to New Scope Wizard-->Next

 

 

 

 

7. Enter the name of the scope ex. “sysbbsr” it can be same as domain name-->Next

 

 

8. You can enter here the range of ip-address you wish to be distributed by the DHCP Server (as-per your requirements) -->Next.

 

 

 

9. In Add Exclusion window you can enter the ip-addresses which you wish to be excluded from automatic distribution of ip by the DHCP (a type of reservation-->Add.

Suppose you don’t want the ip-address of the Server and Router or Switch to be distributed by the DHCP to client systems, in that can you can exclude those ip-address

 

 

 

10. The excluded ip-address is added-->Next

 

 

 

11. Lease duration, leave it as default-->Next

 

 

 

 

 

 

 

 

12. Select 1^st option “Yes I want to configure these options now-->Next

 

 

 

13. If you want to add the router/switch ip-address add it or leave it blank-->Next

 

 

 

 14. Enter the Parent Domain Name (which we have configured here i.e. sysbbsr.com), then enter the server name (i.e. the name of the computer on which domain is being configured) and its ip-address and now click on RESOLVE (and it will resolve the ip-address and the name of the server) the click on -->Add-->Next

 

 

 

 

 

 

 

 

15. Enter the WINS Servers (keeping VPN configuration in mind) ip address, server name is the name of the system ex. sys and it WINS is being hosted on this system hence the ip-address of the system as well as domain is same (220.120.100.11)-->Add-->Next

 

 

 

 

16. Select the 1^st option “Yes I want to activate the scope"-->Next

 

 

 

 

 

17. Click on Finish.

 

 

 

 

 

18. Now you will see the active DHCP (but before seeing active DHCP you have to authorize it) .How to authorize the DHCP is shown below.

 

 

 

 

27. Click on Action-->Authorize

 

DHCP is finally configured.!!!!

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