What Is DHCP and How the Dynamic Host Configuration Protocol Works
Dynamic Host Configuration Protocol, i.e. DHCP is a protocol that assigns IP addresses to devices on a network. Every device that connects to the internet, requires an IP address and its usually assigned by the router that is running a DHCP server. On large networks a router alone cannot manage all the devices that connect to it and a dedicated server handles the IP addresses. The DHCP protocol runs on the server as opposed to the router.
DHCP doesn’t just assign IP addresses, it also handles the configuration for the subnet mask, default gateway, and the DNS service.
DHCP Architecture
There are three components within the DHCP architecture; a DHCP client, a DHCP server, and relay agents.
A DHCP client is any device that can connect to a network, and can communicate with a DHCP server. This includes phones and computers but also network printers and servers.
A DHCP server is the device that assigns IP addresses.
DHCP relay agents requests between DHCP clients and servers. They’re not an essential part of a network however, when dealing with large, complex networks they become a necessity.
DHCP Lease
An IP address, when assigned to a device, has a limited life span. The IP address that your computer, for example, has one day may not be the same one the next day. If the system remains or returns to a network before the lease expires, it will be assigned the same IP address. If however, the lease has expired the device i.e., your computer, is assigned a new IP in the network.
A device can also request to renew the DHCP lease. This effectively fetches a new IP address for the device. The settings for this can be found in the network settings on your computer, or the WiFi settings on your phone.
Purpose Of DHCP
DHCP is essential given how many devices can now connect to a network. It’s essential that a device can quickly get an IP address and that there are no IP conflicts. In the absence of DHCP, IP conflicts alone would prevent them from connecting quickly and easily which in turn is a network management problem in itself. Manually assigning IP addresses, or even resolving IP conflicts can be an tedious, time consuming process even on a small network. On larger networks, it’s practically impossible.
DHCP basically lets network administrators automate the process of assigning IP addresses and because the addresses are dynamic, it’s rare that an address isn’t available for a device. This allows an almost unlimited number of devices to connect to a network.
IP Conflicts & DHCP
Since DHCP is responsible for assigning IP addresses, it stands to reason that it’s the cause of IP conflicts. An error in DHCP does indeed cause IP conflicts however, it can correct itself on the fly. Often when you see the IP conflict error on your system, simply dismissing it is enough to fix the problem. If the problem persists, you should try restarting your router. If it doesn’t go away, you might have a bigger problem on your hands that goes beyond your router and even DHCP.
