What is the purpose of having a DHCP Discover and a DHCP request message?
Sent by the client as the first step of the DHCP client/server interaction. The purpose of the DHCPDISCOVER is for the client to “discover” what servers are out there and what network parameters they have to offer.
What is a DHCP Discover message?
The DHCPDISCOVER message contains an identifier unique to the client (typically the MAC address). The message might also contain other requests, such as requested options (for example, subnet mask, domain name server, domain name, or static route). The message is sent out as a broadcast.
What are the different DHCP messages?
Option 53 defines DHCP message types, including the DHCPDISCOVER, DHCPOFFER, DHCPREQUEST, DHCPACK, DHCPNAK, DHCPDECLINE, DHCPRELEASE, and DHCPINFORM messages.
What is the main role of the DHCP Discover message?
When a DHCP server receives the DHCP Discover message from the client, it also broadcasts a DHCP Offer message over the Ethernet network (because the client IP address has not been allocated yet), informing the client that it is available.
Why do hosts need ARP?
Why ARP is necessary ARP is necessary because the underlying ethernet hardware communicates using ethernet addresses, not IP addresses. Suppose that one machine, with IP address 2 on an ethernet network, wants to speak to another machine on the same network with IP address 8.
What is better DHCP or static IP?
Conclusion. After comparing DHCP vs static IP, it is undoubtedly that DHCP is the more popular option for most users as they are easier and cheaper to deploy. Having a static IP and guessing which IP address is available is really bothersome and time-consuming, especially for those who are not familiar with the process …
What is the purpose of the DHCP release message?
The DHCP release message tells the dhcp server that you want to cancel the ip address offered. The DHCP server will not issue an ack of recipt of the client’s DHCP request. If the release message is lost then the dhcp server retains the ip address until the lease time expires.
Who is the DHCP Discover sent to?
client
The client discovers a DHCP server by broadcasting a discover message to the limited broadcast address (255.255. 255.255) on the local subnet. If a router is present and configured to behave as a BOOTP relay agent, the request is passed to other DHCP servers on different subnets.
What are the 4 types of DHCP packets?
The complete DHCP exchange involves four types of packets: Discover, for your computer to locate the DHCP server; Offer, for the server to offer an IP address; Request, for your computer to ask for an offered address; and Ack, for the server to grant the address lease.
What are the five DHCP messages?
DHCP Messages, DHCPDiscover, DHCPOffer, DHCPRequest, DHCPAcknowledgment, DHCPNak, DHCPDecline, DHCPRelease, DHCPInform. Following are the important messages exchanged between a Dynamic Host Configuration Protocol (DHCP) client and a DHCP Server.
Is ARP a layer 3 protocol?
ARP works between Layers 2 and 3 of the Open Systems Interconnection model (OSI model). The MAC address exists on Layer 2 of the OSI model, the data link layer. The IP address exists on Layer 3, the network layer.
What is the point of ARP?
The purpose of ARP is to resolve addresses by finding the MAC address that corresponds to an IP address. Even though a sending system may know the IP address it wants to ultimately send data to, it may not know the MAC address.
When does a DHCP server receive the DHCP discover message?
When a DHCP server receives the DHCP Discover message from the client, it also broadcasts a DHCP Offer message over the Ethernet network (because the client IP address has not been allocated yet), informing the client that it is available.
How does the DHCP server respond to a DHCP request?
DHCP servers on a network that receive a DHCP Discover message respond with a DHCP Offer message, which offers the client an IPv4 address lease. Clients accept the first offer received by broadcasting a DHCP Request message for the offered IPv4 address. The server accepts the request by sending the client a DHCP Acknowledgment message.
How does DHCP check for an IP address?
The DHCP server which received the DHCP Request message from the client checks if the IP address shown in the DHCP Server Identifier (option 54) field matches its own. If it does, it broadcasts a DHCP Ack message ensuring the client can receive the message (Note: the client has NOT been allocated an IP address yet).
What is the source IP address of a DHCP request?
The DHCP Request Message header has the following main fields: Now, as you can see, still Client Source IP address is 0.0.0.0. This is because the client still didn’t get an IP address from DHCP Server. Also, this message has broadcast only at the network layer of the OSI Model.