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LAB: DHCP Relay Agent

Our Objectives:

1. Upper router will be configured as a DHCP Server, which will provide IP information to 4 regions (Green, Purple, Yellow, Blue) of 2 Branches

2. Hosts of Green color region will get IP of 10.10.10.0/24 Network.

Hosts of purple color region will get IP of 10.10.20.0/24 Network.

Hosts of Yellow color region will get IP of 10.10.30.0/24 Network.

Hosts of Blue color region will get IP of 10.10.40.0/24 Network.

3. WEB-Server of Green Region will get Fixed IP (10.10.10.2/24) from DHCP Server

4. FTP-Server of Blue Region will get Fixed IP (10.10.40.2/24) from DHCP Server

5. You have to configure DHCP Snooping feature into Core-Switch

Let’s Start guys!!!!!!!!!!

1. We will configure IN-DC-DHCP-Server first. From here we will access internet.

WAN side configuration(Internet Access from DHCP Router) & LAN side configuration

IN-DC-DHCP_Server

[WAN side configuration(Internet Access from DHCP Router)]

IN-DC-DHCP_Server#conf t

IN-DC-DHCP_Server(config)#int f1/0

IN-DC-DHCP_Server(config-if)#ip add dhcp

IN-DC-DHCP_Server(config-if)#no shut

IN-DC-DHCP_Server(config-if)#do sh ip int brief

[For Accessing Internet { For resolving Name from IP address }]

IN-DC-DHCP_Server(config)#ip domain lookup

IN-DC-DHCP_Server(config)#do ping google.com [you should get google access now]

=========================================================

[LAN side Configuration by Setting IP statically]

IN-DC-DHCP_Server(config)#int f0/0

IN-DC-DHCP_Server(config-if)#ip add 172.16.1.1 255.255.255.252

IN-DC-DHCP_Server(config-if)#no sh

===========================================================

DHCP Server Configuration by creating 4 pools

IN-DC-DHCP_Server(config)#hostname server [Changing the hostname ]

server(config)#ip dhcp pool 10-Net

server(dhcp-config)#network 10.10.10.0 255.255.255.0

server(dhcp-config)#default-router 10.10.10.1

server(dhcp-config)#dns-server 8.8.8.8

server(dhcp-config)#ip dhcp pool 20-Net

server(dhcp-config)#network 10.10.20.0 255.255.255.0

server(dhcp-config)#default-router 10.10.20.1

server(dhcp-config)#dns-server 9.9.9.9

server(dhcp-config)#ip dhcp pool 30-Net

server(dhcp-config)#network 10.10.30.0 255.255.255.0

server(dhcp-config)#default-router 10.10.30.1

server(dhcp-config)#dns-server 8.8.4.4

server(dhcp-config)#ip dhcp pool 40-Net

server(dhcp-config)#network 10.10.40.0 255.255.255.0

server(dhcp-config)#default-router 10.10.40.1

server(dhcp-config)#dns-server 1.1.1.1

At Core-Switch Configuration:

Sometimes you may see such kind of below message.

Then, what we will do?

By Default, Switch port is enabled by Half-Duplex Mode. However, Router port is Full Duplex. That is why there will appear a miss match error. Therefore, you have to configure switch port as full duplex mode.

Here, I have used "no negotiation auto" command. By default, auto negotiation is enabled in switch. That is why "duplex full" command may not be executed. If there is problem with this "duplex full" command then you should use this "no negotiation auto" command.

Switch

vIOS-L2-01(config)#int range g0/0-1 [2 interfaces are configured by range command]

vIOS-L2-01(config-if-range)#no negotiation auto

vIOS-L2-01(config-if-range)#duplex full

HO Router Configuration:

HO Router

HO(config)#int f0/0

HO(config-if)#ip add 172.16.1.2 255.255.255.252

HO(config-if)#no sh

HO(config-if)#int f1/0

HO(config-if)#ip add 192.168.1.1 255.255.255.252

HO(config-if)#no sh

HO(config-if)#int f2/0

HO(config-if)#ip add 192.168.1.5 255.255.255.252

HO(config-if)#no sh

HO(config-if)#do wr

BR-1 Router Configuration:

BR-1 Router

BR-1(config)#int f0/0

BR-1(config-if)#ip add 192.168.1.2 255.255.255.252

BR-1(config-if)#no sh

BR-1(config-if)#int f1/0

BR-1(config-if)#ip add 10.10.10.1 255.255.255.0

BR-1(config-if)#no sh

BR-1(config-if)#int f2/0

BR-1(config-if)#ip add 10.10.20.1 255.255.255.0

BR-1(config-if)#no sh

BR-1(config-if)#do wr

BR-2 Router Configuration:

BR-2 Router

BR-2(config)#int f0/0

BR-2(config-if)#ip add 192.168.1.6 255.255.255.252

BR-2(config-if)#no sh

BR-2(config-if)#int f1/0

BR-2(config-if)#ip add 10.10.30.1 255.255.255.0

BR-2(config-if)#no sh

BR-2(config-if)#int f2/0

BR-2(config-if)#ip add 10.10.40.1 255.255.255.0

BR-2(config-if)#no sh

BR-2(config-if)#do wr

Routing Protocol implementation into all routers

Server	HO
server(config-router)#router rip server(config-router)#net 172.16.1.0 server(config-router)#no au	HO(config-if)#router rip HO(config-router)#version 2 HO(config-router)#net 172.16.1.0 HO(config-router)#net 192.168.1.0 HO(config-router)#net 192.168.1.4 HO(config-router)#no au
BR-1	BR-2
BR-1(config-if)#router rip BR-1(config-router)#version 2 BR-1(config-router)#net 10.10.10.0 BR-1(config-router)#net 10.10.20.0 BR-1(config-router)#net 192.168.1.0 BR-1(config-router)#no au	BR-2(config-if)#router rip BR-2(config-router)#version 2 BR-2(config-router)#net 10.10.30.0 BR-2(config-router)#net 10.10.40.0 BR-2(config-router)#net 192.168.1.4 BR-2(config-router)#no au

Relay Agent Configuration & Verification

Router	Interface	Connected local subnet
BR-1	Fa1/0	10.10.10.0/24
BR-1	Fa2/0	10.10.20.0/24
BR-2	Fa1/0	10.10.30.0/24
BR-2	Fa2/0	10.10.40.0/24

Therefore, we have to configure the DHCP-Relay at those ports.

Configuration:

BR-1

BR-2

BR-1(config)#int f1/0

BR-1(config-if)#ip helper-address 172.16.1.1

BR-1(config-if)#int f2/0

BR-1(config-if)#ip helper-address 172.16.1.1

BR-2(config)#int f1/0

BR-2(config-if)#ip helper-address 172.16.1.1

BR-2(config-if)#int f2/0

BR-2(config-if)#ip helper-address 172.16.1.1

Verification:

We are getting IP by dhcp from my DHCP-Server into WEB-Server & FTP-Server. See below image. Means our DHCP server is able to give IP information to all client devices because of

DHCP Relay Agent configuration is working properly.

Here, WEB-Server is located into 10-Network. It is getting from 10-Net Pool properly. It’s IP=10.10.40.2

Here, FTP-Server is located into 40-Network. It is getting from 40-Net Pool properly. It’s IP=10.10.40.2

MAC Binding Configuration

Now, we want that, WEB & FTP servers will get fixed IP from relative pool.

WEB-Server will get a fixed IP like – 10.10.10.100/24

FTP-Server will get a fixed IP like – 10.10.40.100/24

As, already DHCP server has given IP info to those servers, so already a binding is created. We have to clear those first. Otherwise when we will configure binding process an error message will appear.

We will clear those bindings by “clear ip dhcp binding *” command. Here, * à means all entry will be cleared. If you want to clear specific entry, you can also do that by setting that specific IP instead of * . Like if I want to clear only 10.10.10.2, then we will give à clear ip dhcp binding 10.10.10.2

Now we will configure the MAC-Binding process at DHCP-Server.

** Note: Here need client-identifier, which we will get by “show ip dhcp binding” command. You need to copy from “Client ID/Hardwer Address/User Name” part & paste it into a notepad. Then it needs to organize as like below image.