Dynamic Host Configuration Protocol (DHCP)-2

 

First Part Link: 

https://itbd-training.blogspot.com/2021/08/dynamic-host-configuration-protocol-dhcp.html

Our scenario was like below diagram

                                        

Now, We will do some extra work on DHCP server. 

Clients will get IP information automatically. So, it may happen that our clients get IP randomly; which means different IPs every time, not the same throughout and it can be problematic. Suppose if we use a File Server within our company where every user keeps & shares their necessary resources; If that File Server's IP changes everyday, users will face problem. That's why, we need to fix that IP where the file Server should get a fixed IP everyday.

So we will use MAC binding. Let's say, File Server will get an IP - 192.168.1.100 at everyday. So we will fixed this IP only for File Server. No other DHCP clients will not get this IP.

MAC Binding : 

We will bind an IP address with Server's MAC address. Simply this is called MAC binding.

Let's GO dear. It is very easy task. Right? Yep. Let's start !!!!

First we will see our DHCP binding database from DHCP server. From that we need the File-Server's hardware address to bind with IP address. At last session, we saw that our File Server got 192.168.1.3.

DHCP-Server#show   ip   dhcp   binding

So, we have got our File-Server's Client ID/Hardware Address.

Which is   : 0100.5079.6668.02

Now, we will bind this client ID with 192.168.1.100. So that when a DHCP request will receive DHCP server from this ID, Server always will provide an same IP(192.168.1.100) at everyday. Which will be fixed for File-Server.

For doing that we have to clear this binding list at first by below command

DHCP-Server# clear ip  dhcp binding  192.168.1.3                          

If you use * instead of specific IP, all information will be cleared. 

DHCP-Server# clear ip  dhcp binding *

DHCP-Server(config)#ip dhcp pool FS-Binding

DHCP-Server(dhcp-config)#client-identifier  0100.5079.6668.02

DHCP-Server(dhcp-config)#host  192.168.1.100

See, File Server has got  192.168.1.100 IP.

Exclusion Address: 

Now if we want, DHCP Server will not provide 10.1.1.2   to  10.1.1.100, then we have to exclude this range. We can exclude specific IP (10.1.1.102) also. So, now clients will not get 10.1.1.2 - 10.1.1.100  & 10.1.1.102 IPs.

DHCP-Server(config)#ip dhcp excluded-address 10.1.1.2 10.1.1.100

DHCP-Server(config)#ip dhcp excluded-address 10.1.1.102

Now, If   PC1 & Client-1 request for IP to DHCP Server, DHCP-Server will not provide these range and specific IP. See below images

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Alhamdulillah, We have done our basic Tasks

Next Step, we will configure DHCP Relay Agent.

Any doubt dear about this topic? Please comment if any issue there.

Part-3 Link: 

https://itbd-training.blogspot.com/2021/06/lab-dhcprelay-agent-our-objectives-1.html