DHCP
In this article, I explain about DHCP Server role and how to install it on Windows Server 2016 with the help of the screenshots for an easy understanding purpose. DHCP stands for Dynamic Host Configuration Protocol. Dynamic Host Configuration Protocol (DHCP) allows the Servers to assign or lease IP addresses to the clients/ computers, which are enabled as DCHP Clients/ Computers in network environment. In simple words, this DHCP is used to simplify the configuration of IP Clients in a network environment. It reduces the administrative work by using an automatic IP configuration. Now, let’s begin with the installation process of DCHP Server role on Windows Server 2016.
DCHP Server role installation process is pretty much similar to most of the other Server roles, which we install, using Server Manager on Windows Server 2016. Let me show you how do we install with the help of some screenshots, which I’ve taken while installing DHCP Server role on my machine. (In part II article)
Note
Configure at least one static IP address on your computer before installing DHCP.
DCHP Lease Generation Process
DHCP Lease generation process is a four step process. It is also known as D O R A process. It’s very simple and easy to understand. Let’s see how this DHCP Lease generation process works.
- D- Discover
- O- Offer
- R- Request
- A- Acknowledge
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Let me explain this lease generation process with a funny conversation between Server and Client (let’s just assume ).
- Discover
In this first step, Clients that are DHCP enabled and have no IP addresses and are assigned will broadcast on the network and say
Client
“Hey, I’m a client machine on this network, who’s been looking for an IP address. Is there a DCHP Server out there, who can help me?
- Offer
In this second step, if any DCHP Server hears DHCP Discover ( from step 1), it will broadcast out and says
DHCP Server
“Hi,I am a DHCP Server. Here is an offer of an IP address, if you’d like to have it). “
- Request
This is where the client machines accepts the offer (IP address) from DHCP Server and broadcasts out back to to DHCP Server, which says
Client
Okay, I would like that IP address and thank you so much ) “
- Acknowledge
DCHP Server sends an acknowledgement to the client with the lease information.
DHCP Server
Okay, I acknowledge it and now you have that IP address).
Above is just an example for an easy understanding purpose.
Now, let’s try to understand DHCP lease renew process.
DHCP Lease Renewal Process
This lease renew process is also very easy to understand. The scope of the IP address lease period is limited to 8 Days (by default), i.e if a client leases an IP address from a DCHP Server, the lease period is valid only for 8 days, then it has to renew its lease to remain active on the network. Let’s not worry about this renewal process, because all the clients will attempt to renew its lease as 50% of the lease duration has expired. Let’s see how this works?
Steps
If a client leases an IP address from a DHCP Server, by default, it will get it for 8 days.
- Scope Of DCHP Lease Period ———————————— > 8 DAYS (By default).
As I said above, each client will attempt to renew the lease after 50% (4 days), the lease duration has expired.
- So, after 50% means ——————————————> 4 DAYS
Now after 4 days, if a client attempts to renew its lease, but if the Server doesn’t respond? What do you think will happen? Well, let’s not worry about this..! Because even if the Server doesn’t respond after 4 days (50%). We still have 4 more days, right?, so the client will again try to attempt to renew its lease after 2 days (50% of 4 days).
- This means, after 75% —————————————————————> 6 DAYS
Let’s say DCHP Server doesn’t respond after 6 days. Now, we have 2 more days. So the client will again attempt to renew its lease after 1 day i.e after 7 days and
- After 87.5 % —————————————————————————> 8 DAYS…
Here, if the Server still does not respond,then the full DCHP lease generation process ( D O R A Process ) starts over again. This is how the lease generation and renewal process works in DHCP. I will be explaining the installation process of DHCP Server role in PART II.