PPA.Lab - Dynamic Host Configuration Protocol
GNS3
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GNS3
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.pcap fileIn the early days of networking, when a device wanted to communicate over a network, it needed to be assigned an address by hand.
As networks grew, this manual process quickly became cumbersome. To solve this problem, Bootstrap Protocol (BOOTP) was created to automatically assign addresses to network-connected devices.
BOOTP was later replaced with the more sophisticated Dynamic Host Configuration Protocol (DHCP).
DHCP is an application-layer protocol responsible for allowing a device to automatically obtain an IP address (and addresses of other important network assets, such as DNS servers and routers).
Most DHCP servers today also provide other parameters to clients, such as the addresses of the default gateway and DNS servers in use on the network.
Indicates whether the packet is a DHCP request or a DHCP reply
The type of hardware address (10MB Ethernet, IEEE 802, ATM, and so on)
The length of the hardware address
Used by relay agents to assist in finding a DHCP server
A random number used to pair requests with responses
Seconds since the client first requested an address from the DHCP server
The types of traffic the DHCP client can accept (unicast, broadcast, and so on)
The client’s IP address (derived from the Your IP Address field)
The IP address offered by the DHCP server (ultimately becomes the Client IP Address field value)
The DHCP server’s IP address
The IP address of the network’s default gateway
The client’s MAC address
The server’s hostname (optional)
A boot file for use by DHCP (optional)
Used to expand the structure of the DHCP packet to give it more features
The DHCP initialization process is often referred to as the DORA process because it uses four types of DHCP packets: discover, offer, request, and acknowledgment.
