How to Configuring IP DHCP Helper Address

So have you thought about how a single DHCP server can provide a DHCP IP address to each computer on a network, DHCP servers are not in the same broadcast domain? All DHCP request broadcast requests correctly?

A lot of people who are getting on-campus or CCNA online training don't know how to do this, but the answer is quite simple. This is called IP assistance programs address. DHCP IP assistance programs address previous routing interfaces (such as VLAN or a router Ethernet interface allows the specific device will act as a "middle man" forwards (broadcast) BOOTP DHCP requests it receives by assisting programs through unicast IP address of the DHCP server IP address configured on the interface.

To configure IP assistance program addresses connected to interface configuration mode in which you want to provide DHCP broadcast domains on the interface using the IP address a.b.c.d IP assistance programs address. For example, one VLAN on the interface or router's Ethernet interface to connect Cisco switch or have a separation layer 2 VLAN.

R1 and R2 in the lab put a different VLAN, your DHCP pool is created for each VLAN on the R1 and SW1 ′ s VLAN20 interfaces connected to R2 VLAN in order to ensure that the device on the Ethernet segment from the DHCP server (R1) receive assistance program a IP address is configured on the DHCP IP address. You will test your PC as a simulated host using the R2 configuration of DHCP and IP assistance programs.

Familiarize yourself with the following new commands;

• Than load if you use GNS3 CCNA free Binder GNS3 topology than starting system R1, R2 and SW1
• Establish a with R1, R2 and SW1 than load by copying the configuration file from the text box and paste it into a respectable router console provides the following initial configuration of the device console session.

Step 1: On R1 create a new DHCP pool called “LAB_POOL2″ and assign it the following attributes; network 10.116.20.0/24, default-router of 10.116.20.2, domain name TESTLAB.LOCAL, DNS servers 10.116.18.6 & 10.116.18.7

Step 2: About the SW1 IP interface configuration assistance programs address points to 10.116.10.1

Step 3: Verify that R2 can receive a DHCP address from R1 in the 10.116.20.0/24 network.

R2#configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

R2(config)#interface FastEthernet0/0

R2(config-if)#shut

R2(config-if)#

%LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down

R2(config-if)#no shut

R2(config-if)#end

R2#

%SYS-5-CONFIG_I: Configured from console by console

R2#

%LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

R2#

%DHCP-6-ADDRESS_ASSIGN: Interface FastEthernet0/0 assigned DHCP address 10.116.20.3, mask 255.255.255.0, hostname R2

R2#ping 10.116.10.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.116.10.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 48/108/164 ms

R2#