Need help in configuring DHCP Server across edge switches

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May 26th, 2007
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Hi guys


I have a cisco 4503 core switch and about 5 edge switches 3560 , one for each floor in my office.


I have configured a dhcp server with the respective number of scopes as number of vlans which is 6 in this case.


Ive set the IP helper address and everything on the core switch and am able to get the right ip address from the right scope when the hosts are directly connected on the core switch.


But it does not happen from the edge switch, do the edge switches need any configuration?


the cisco 4500 is a VTP server and all the edges are in client mode


and on the respective edge switches i have configured the first 20 ports to the Vlan on the floor they belong and left the other 4 as trunk ports to my core switch (fibre).


I can see that the edge switches have recvd the vlans from the core.. and the ports moved into the respective vlans.. but i cannot get dhcp ip address's :-(


can anyone guess what im doing wrong?

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Amit Singh Sat, 05/26/2007 - 20:58
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Hello,


What is the gateway for the hosts connected to the edge switches. Is it the 4503 Vlan SVI? Please paste the switch config for Core and anyone of the edge switch.


-amit singh

kpawankumar Sun, 05/27/2007 - 03:21
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I can paste the configuration later in the night when i get to the other office.. but here's the summary


Core Switch


VTP - Server Mode


Vlans Created

1) Vlan 1000 (for servers)

2) Vlan floor1

3) Vlan floor2

4) Vlan Floor3


DHCP server ip add: 10.56.0.11

Servers have static ip addresses in the 10.56.0.0 / 128 range

and all the edge switches have ip addresses 10.56.130 / 128 onwards


Vlan configuration on the core switch:


1) Vlan floor1


IP address 10.56.1.1 255.255.255.0

Ip helper address 10.56.0.11

no shut


2) Vlan floor2


IP address 10.56.2.1 255.255.255.0

Ip helper address 10.56.0.11


3) Vlan 200 (For switches)

Ip address 10.56.0.129 255.255.255.128

ip helper address 10.56.0.11


on the edge switch on floor 1 .. it receives all the vlans

and i moved the first 20 gi ports to Vlan floor1 ..


Config on this switch


Ip default gateway 10.56.0.129


Vlan floor1

ip address : nothing

ip helper address - 10.56.0.11


vlan 200

ip address 10.56.0.130 255.255.255.128

ip helper address 10.56.0.11


and the other 4 ports are in trunk mode .. one of the ports is connected to the core switch via a fibre cable.


does this help ? hoping im not doing anything wrong...



Amit Singh Sun, 05/27/2007 - 08:49
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  • Cisco Employee,

I hope you also have created a SVI for vlan 1000 on the core switch. Have you really, as I dont see it in the config above? Your config seems to be fine.


You said earlier, that you are getting the IP's when you connect to the core switch.I would first check the inter-vlan connectivity on the core switch. If the intervlan routing is working fine when you connect to the core switch, then check your trunk link settings on all the switches.After that, try setting up a static IP on the hosts in one of the vlan and try ping the DHCP server and check if you are reaching the DHCP server.If you are reaching the DHCP serverthen you should get the proper DHCP after the above steps.


HTH,Please rate if it does.


-amit singh

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