DHCP stands for dynamic host configuration protocol which allows a computer to join an IP-based network without having a pre-configured IP address. Also, it is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the concerned network.
Internet service providers usually use DHCP to help customers join their networks with minimum setup effort required. Likewise, home network equipment like broadband routers offers DHCP support for added convenience in joining home computers to local area networks (LANs).
APIPA is an another feature for combating DHCP failover mechanism over local networks which essentially stands for Automatic Private IP Addressing. With APIPA, DHCP clients can readily obtain IP addresses when DHCP servers are non-functional. APIPA prevalence is in all modern versions of Windows except Windows NT.
When a DHCP server fails, APIPA allocates IP addresses in the private range from169.254.0.1 to 169.254.255.254.There after, clients can verify their address which is unique on the network using ARP. Now, when the DHCP server is again able to service requests, clients can update their addresses automatically on the concerned network using APIPA. In APIPA, all devices use the same default network mask 255.255.0.0 and all reside on the same subnet.
APIPA is enabled on all DHCP clients in Windows unless the computer's Registry is altered to disable it. APIPA can be enabled on individual network adapters also.
Since, APIPA uses unique IP addresses in the private Class B space, therefore, APIPA is generally useful on home or other small intranet LANs.
For establishing a DHPC-based LAN firstly Decide what range of IP addresses you would like to use. You should use a "Private IP Range", otherwise you could have problems related to traffic to and from your network being routed incorrectly. For a simple LAN, stick with 192.168.0.100, a subnet mask of 255.255.255.0 and a pool size of 50 would allow up to a maximum of 50 machines to be set up on your network without having to change anything.
Secondly, set the IP address of your computer to 192.168.0.2 with a subnet mask of 255.255.255.0 (an address in the same subnet as the addresses in the pool, but not an address in the pool itself).Then, Download tftpd32 from http://tftpd32.jounin.net/ from the archives folder. Thereby, unzip the file to your computer and run tftpd32.exe. Then, click Settings option.
Next, Select the DHCP tab in the Settings window. After which, Set the "IP pool starting address" to the address you want the first computer to have working on DHCP. (192.168.0.100 if you're not sure).Next, Set the "Size of pool" to a little more than the number of computers and devices you think you'll need on your LAN. (if in doubt, 50 is a suitable number) After which, Leave the "Boot File" field blank
Now, if you have a DNS server on your network, or one accessible to the machines on your network, enter it's IP address in the "WINS/DNS Server" box. If you don't know what it means, then, leave it blank. Then, Set "Mask" to your subnet mask. If you don't know what it is, follow the aforesaid addressing scheme and set it to 255.255.255.0. After which, leave the "Domain Name" and "Additional Option" boxes as they are. After which Press "Save".
Thus, on performing the above mentioned procedure, DHCP server would be set up on your computer with its enhanced connectivity for intranet & internet purposes.