DHCP FAQ

1. What is DHCP?
DHCP stands for Dynamic Host Configuration Protocol. It offers configuration services for hosts. When a host is powered up, it can use DHCP to get its configuration information from DHCP server. Commonly used host configurations are IP address, gateway address, DNS address.
2. Why DCHP.
Manually configuring one host a time could be tedious and error prone. Two major benefits of DHCP are:
- Duplicated IP address. It's hard to track IP addresses with manual configuration.
- When IP address is short supply, it’s inefficient to allocate IP addresses to computers that are powered off.
- Assist host to configure TCP/IP,
3) What is the scope of DHCP?
DHCP is limited within one broadcast domain. It does not cross routers.
4) How many DHCP servers in a LAN?
There are no hard number limits. Usually, we run DHCP server at gateway routers. In large LAN networks, we provide a pool of routers as gateway to avoid single point of failure. E.g., Cisco HSRP. In such cases, each router runs a DHCP server.
5) What is the structure of DHCP packets?
They are all layer 2 frames that carry link headers but no network layer headers. The host won’t be able to assign the source IP address in network header until it is granted an IP address from a DHCP server.
Learn more: DHCP Basic