Dynamic Host Configuration Protocol (DHCP) is the protocol which assigns an IP address to the devices that are available on the network. Every System Administrators around the uses DHCP to automatically assigns the IP rather than manually assigning them.
How DHCP Works
DHCP Server is required to setup to enable the DHCP environment with good configuration parameters of the given network.
DHCP follows the client/server protocol automatically and managed centrally.
A DHCP Server contains Pool of IP Address that are allocated to all the devices during the boot of the network. Since it is so dynamic and not static any IP address that is not in use is dynamically returned back to the pool for reallocation process.
List of Keys is maintained by a network administrator in the DHCP Servers which include TCP/IP configuration Information and IP Address Pool, Subnet masks and the network gateways.
If you are a DHCP-enabled Client then all the above info can be retrieved from the servers when needed. Since the configurations Information is stored in a database on the server.
DHCP Allocation Types
DHCP on larger networks works for the allocation of the IP for the entire network. Depending on the Implementation there are three methods of allocating IP Address.
- Dynamic Allocation
- Automatic Allocation
- Manual Allocation (Static Allocation)
Dynamic Allocation – A network administrator allocates a range of IP address for the DHCP. During initialization the devices that are connected to the network in the LAN requests for an IP. A time duration is set for the process to complete else the free IPs are acquired back by the DHCP.
Automatic Allocation – The allocation process is very similar to that of the Dynamic but the DHCP server maintains a table of previously assigned IP addresses to the devices and re-assigns the same IP Address when it requests for connection.
Manual Allocation – Based on the client’s MAC Address the DHCP servers gives a Private IP Address that the Administrator makes a map with these predefined IP Addresses. Each call this features differently in Netgear router it is called as Address Reservation, Cisco Router & Linksys Router the term DHCP reservation or static DHCP.
DHCP & ISPs
Internet service providers (ISPs) use DHCP to allocate the Public IP Address to their customers. The Traditional IPv4 Addresses are becoming sparse so it allows them to use it very efficiently by getting back the IP Address if the subscriber keeps them unused for a longer time.
Benefits of DHCP
- We do say IP address configuration is very reliable because DHCP minimizes conflicts and errors caused due to manual configuration of IP Address.
- Typographical Errors or Address conflicts caused by assigning the same IP to more than one computer can be avoided.
- Since the DHCP is centralized and autonomous there is a reduced network administration.
- Efficient IP Handling. For eg: If you are using a portable computer or a handheld device like phones or tablets then moving around the Wireless network is possible so these clients IP address changes and are updated frequently.
- In each sub, et an even simpler option is present instead of using DHCP Server a DHCP relay agent performs the Initial DHCP messages forwarding.