Question about DHCP

starnixon

Hello guys, im trying to figure out a problem in my mind, but i am not finding the answer...

When a computer first connects to a network, he sends out a message to the broadcast adress, looking for a DHCP server to give him an ip adress right?
My question is, if the computer doesen't have an ip adress, how can it know the broadcast adress for that network?
How does it know , that the broadcast adress is 192.168.0.255 and is not 192.168.23.255 or 10.25.255.255 for example...?

I just started to read compTIA Network+ book, i never ever had contact with networking before i start reading this book.
I am a person that can only understand something when it makes logical sense, so i really like to go to the bottom of every subject to understand how it really works.
Thank you in advance.

Moldygr33nb3an

The PC sends out a broadcast using its MAC address as the source address and the global broadcast address (FF:FF:FF:FF:FF:FF) as the destination address across the network until it finds the router. It's called a DHCPDiscover message.

starnixon

Oh ok , so when that global broadcast adress (FF:FF:FF:FF:FF:FF) get's to the router, it will then find a DHCP server for the computer, and establish the connection between both?

Moldygr33nb3an

Pretty much. It is a 255.255.255.255 ip address and the computer is pretty much saying "Hello DHCP, I'm here, where are you?" across the subnet. The DHCP eventually gets that message and reply's with a DHCPOFFER message.

Moldygr33nb3an

Here is some more info.

What is DHCP and How DHCP Works? (DHCP Fundamentals Explained))

Step by Step towards the middle - Layer 3

starnixon

Oh ok , thank you very mutch for the reply.
I am currently studying for the comptia network+ exam, right after that I will go for ccna certification, so you will probably see me around here a lot.
Thank you again you were very helpful .

Moldygr33nb3an

Good luck, buddy!