cisco 3750 - ip-helper doesn't work

[dmeligrana_insud]

Hello.

        We have a cisco 3750,  ip routing enabled, service dhcp (enabled), 2 vlans: vlan1=LAN, VLAN 202=cisco Phones. I need the phones to get ip addressing with dhcp. Routing is ok, If static address is configured,  two points from each vlan see each other.

Now, I've configured ip helper-address on interface vlan202 so that any device plugged to that subnet can get addressing from a Windows DHCP server on VLAN1. Obviously it doesn't work.

any idea?

Thanks.

Regards

[harisivaji]

Are you able to see DHCP traffic in the device

Can you post the running config

Thanks

Hari

[dmeligrana_insud]

Here is an excertp of the config.

I cleared things that should have nothing to do with routing and dhcp features.

...

vtp mode transparent
ip subnet-zero
ip routing
no ip dhcp relay information check
!
...
...
!
port-channel load-balance src-dst-ip
no file verify auto
spanning-tree mode pvst
spanning-tree extend system-id
!
vlan internal allocation policy ascending
!

...
...
!
...
...
!
vlan 202
name VoIP_GI
!

...
...
!
interface GigabitEthernet2/0/20
switchport access vlan 202
switchport mode access
speed 100
duplex full

!
interface GigabitEthernet2/0/25
!
interface GigabitEthernet2/0/26
!
interface GigabitEthernet2/0/27
!
interface GigabitEthernet2/0/28
!
interface Vlan1
ip address 172.16.50.10 255.255.0.0
!
!
interface Vlan202
description VoIP_GI
ip address 172.24.202.1 255.255.254.0
ip helper-address 172.16.15.88
!
ip default-gateway 172.16.1.1
ip classless
ip route 0.0.0.0 0.0.0.0 172.16.1.1

------------------------

System image file is "flash:c3750-ipbase-mz.122-35.SE5/c3750-ipbase-mz.122-35.SE5.bin"

cisco WS-C3750G-24TS-1U (PowerPC405) processor (revision F0) with 118784K/12280K bytes of memory.

There is a route on the DHCP Server pointing to 172.24.202.10, so that it can reach the vlan.

172.24.202.0    255.255.254.0     172.16.50.10     172.16.15.88      

Thanks

[Murad]

Can you ping the DHCP server from the router?

[dmeligrana_insud]

Hello Everyone. This problem was solved. The key issue was that the scope was created into a "Superscope". In order to get it to work, the scope must be created out.

Thanks for your help. At least, the cisco device config was ok.

Regards.