DHCP Discover Message
This is the first message in the DORA process which helps in finding the DHCP server of the network. DHCP client will find the server by sending DHCP discover message. The broadcast message is sent to the network. As the DHCP client doesn’t know the IP address of the server so the message is broadcast with a destination IP is 255.255.255.255. And the source IP will be 0.0.0.0 as the client does not have any IP address. Here the DHCP discover message in the data link layer and network layer is always broadcast.
Source IP address: 0.0.0.0 Destination IP address: 255.255.255.255 Source MAC address: MAC address of DHCP clients Destination MAC address: FF:FF:FF:FF:FF:FF
How DORA Works?
Dynamic Host Configuration Protocol(DHCP) uses the DORA. Dynamic Host Configuration Protocol is the protocol of the application layer. It is used to provide Subnet Mask, Router Address, DNS Address, and Vendor Class Identifier. In fact, DHCP provides an automatic IP address to Hosts which want to connect to a network.
DORA is the process that is used by DHCP. DORA helps in providing an IP address to hosts or client machines. DORA is the process that follows some steps between the server and client. It gets the IP address from the centralized server. It consists of four-stage:
- Discover
- Offer
- Request
- Acknowledge
Now let’s see what happens when DHCP clients request a DHCP server an IP address. Let’s see what messages are exchanged between them in the process.
Note: In the network layer, DHCP messages are always broadcast. In the data link layer also DHCP messages are broadcast.