DHCP relay Agent

Answered Question
Jan 5th, 2009

Dear All;

i need your advice

i have 1 switched network...details are here for your consideration.

enduser first switch is 2950....it has 5 Vlans...Vlan 10-20-30-40 and 50. then i have uplink to another layer 2 switch 3500. i just make these Vlan into this as well. then i have uplink to layer3 3750 fiber switch,. there i make all Vlan and assign the IP address which would be default gateway for the clients those are behind 2950 switch. for DHCP relay ...now i need to configure IP Helper-address on Vlan20...like

#Vlan 20

#ip address 1.1.1.1 255.0.0.0

#ip helper-addres 10.1.1.1

by doing this my DHCP relay would configure...i already check that my client is able to ping the DHCP server.

is this complete configuration..?

please advice

regards

soshomile

Correct Answer by Giuseppe Larosa about 8 years 1 month ago

Hello Soshomile,

if 10.1.1.1 is the DHCP server ip address you are fine.

by default the bootpc requests are converted in packets with destination 10.1.1.1 and with a gateway field 1.1.1.1 that allows the DHCP server to assign a correct ip address from the correct pool to the requesting client.

DHCP server answer is sent to 1.1.1.1 and the router will send out a broadcast for the original client with the answer (the answer contains the MAC address of the requesting client)

Hope to help

Giuseppe

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Correct Answer
Giuseppe Larosa Tue, 01/06/2009 - 01:54

Hello Soshomile,

if 10.1.1.1 is the DHCP server ip address you are fine.

by default the bootpc requests are converted in packets with destination 10.1.1.1 and with a gateway field 1.1.1.1 that allows the DHCP server to assign a correct ip address from the correct pool to the requesting client.

DHCP server answer is sent to 1.1.1.1 and the router will send out a broadcast for the original client with the answer (the answer contains the MAC address of the requesting client)

Hope to help

Giuseppe

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