Why does DHCP use UDP and not TCP?

In this post, we will learn Why does DHCP uses UDP and not TCP. It is a little interesting to learn why DHCP uses UDP.

Port used by DHCP

DHCP uses UDP port 67,68.

DHCP client uses UDP port 67

DHCP server uses UDP port 68

Before understanding why DHCP Uses the UDP not TCP, We have to understand what is UDP and TCP in Brief.

Why does DHCP use UDP and not TCP
TCP and UDP Communication

What is UDP?

UDP stands for User datagram protocol, it is also called connectionless protocol. Whether Packet has reached the destination packet or Unless there is an error message received then the packet is assumed to have reached its destination, it’s up to the application itself to deal with non-replies to UDP packets.

What is the TCP?

TCP stands for Transmission Control Protocol.however, it is a connection orientated protocol. Before any data is sent there is a three-way handshake between source and destination to establish the connection

UDP is much faster than TCP  because TCP uses the three-way handshaking.

As you know DHCP User the DORA Process for automatic network configuration assignment.

DHCP-DORA-Process
DHCP DORA Process

The very first message DHCP sends is DISCOVER which is a broadcast message as the client has no idea what DHCP server’s IP address is. TCP doesn’t support broadcasts as it is connection orientated protocol. so we have to use UDP for the DHCP Process