Dhcp isn't working

[Khundmir4cisco]

I have configured DHCP on my core switch 6500. Though  we already have dhcp server but I just want to configure dhcp on 6500 for test purpose. I have created the pools, created int vlans and set default router for each vlans. The end users connected to the access layer does not fetch ip from DHCP. Please need experts help. 

[Mark Malone]

Hi

Is the user directly connected to 6500 or through another switch ?

is the user on the same broadcast domain as dhcp pool ? if not is ip helper enabled to point to dhcp pool on interface or svi

Can you post the configuration you setup for one of the not working vlans

Is dhcp running -(conf t) service dhcp

have you trued a debug dhcp detail or a span wireshark to see if the offers are being sent out and if the users are receiving them

[Khundmir4cisco]

Thank you for your replr Mark.

There is 6500 Core, in between Distributor 4500, and 3560 Access Layer. The user is connected to the 3560. Yes, they are on the same broadcast domain. When I give static IP it's working but DHCP is not working. 

On the core:

no ip dhcp conflict logging
ip dhcp excluded-address 10.26.37.1 10.26.37.10
ip dhcp excluded-address 10.26.37.254
!
ip dhcp pool p37
network 10.26.37.0 255.255.255.0
default-router 10.26.37.254
domain-name abc.com
dns-server 10.24.160.25
lease 30

!

interface Vlan37
ip address 10.26.37.254 255.255.255.0
ip helper-address 10.27.200.254 (Core Switch IP)

!

On the Distributor:

Created vlan 37, trunked it to the core. 

On 3560 Access:

Created Vlan 37 and assigned ports.

ip default-gateway 10.27.200.254
ip classless
ip route 0.0.0.0 0.0.0.0 10.27.200.254
ip http server

I think I have done some  mistake in the configs steps.

Please help me Mark.

[gchana2011]

Hi,

Just to confirm, have you verified that all trunks upstream from the access switch are carrying VLAN37?

Try creating a loopback on the 6500 and pointing the ip helper address on the SVI towards that IP. You may also have to enable IP routing is not already enabled.

Hope this helps.

[Mark Malone · Accepted solution]

hi if you connect a laptop direct to 6500 switch port with vlan 37 can you get a dhcp address ok ?  this will rule out dhcp issue but config looks ok on 65 but just to be sure

you don't need a helper address under vlan interface as your not moving across different subnets remove that

if access switch is layer 2 only requires default-gateway , make sure you can ping vlan interface ip from pc on access switch  

make sure 3750 is trunking the vlan up and so is 4500 run show int trunk and check aswell no stp blocking for that vlan in path

[Khundmir4cisco]

Thank you for your support.

I have removed helper address and enabled rapid-pvst and it works now.

Thank you.

[Mark Malone]

ah glad to hear :)