2. topology
So in this topology I have made R1 as a DHCP server whereas R2 , R3 and R4 are DHCP clients who
will get the IP address from DHCP server dhynamically.
3. To make DHCP as a server we need to use these commands.
And to get the ip addresses dynamically on the DHCP clients side.
DHCP (dynamic host configuration protocol):-A DHCP server is a network server that automatically provides
And assigns IP addresses to client devices.
4. Once the work of commands has been done the DHCP server will assign IP addresses to every
client who is requesting for the ip addresses. And when are the IP addresses has been assigned
We will get 4 messages in wireshark. i.e
Discover message:- It is the first message in DORA process which is used to Find out the DHCP server in
the network. It will send a broadcast message in the network to find DHCP server with destination IP
255.255.255.255 and with source IP as 0.0.0.0. The client will be having port number of 68 and server
will be having port number of 67
DHCP offer :-When server receives the discover request then it responds with the DHCP offer request
to the client, this contains the information related to IP address, end the lease duration that data host
can use and in here source IP will be DHCP Server’s IP which is 10.1.1.1 and destination IP will be
255.255.255.255
5. DHCP request:-The host receives the offer packet then it replies back with a request message,
this message tells the server that it's ready to accept the IP address that the server offered.
However, the source IP will still be 0.0.0.0 end the broadcast IP is 255.255.255.255
DHCP acknowledge:-The server gets the request from the host that this message is a reply to the offer
message to the host .
It will send the DHCP acknowledgement request to the host along with which will contains the IP address
and the subnet mask that the server allowed for the host .
We can see in Wireshark what IP would be given in the field called your client IP address.
Now I have shutted down one interface who got the ip address of 10.1.1.3 which is R2 to see what
happens.
Then when I checked the Wireshark I got one new message which is DHCP release message.
6. DHCP release :- this happened when I shutted down the interface of my router who got the ip
address of 10.1.1.3 and after when I did no shut again it will give a new ip to the client. And that
was 10.1.1.5. the purpose of DHCP release function is to tell the DHCP client to release the IP
address it has in use and remove its configuration from the interface of the device.
New Ip address assigned . Shown below
Thankyou
