DHCP Problem

[nmorelli]

I have a LAN with 3 vlans on a catalyst 6509 routed by MSFC. On vlan 1 I have a DHCP server and on other 2 vlans (192, 194) clients. I configured "ip helper-address" command with dhcp's IP address. If I put a client on vlan 194 I get right IP address. If I move to vlan 192 I obtain same IP address of vlan 194 scope.

In the traces I see an error message:

there is no address pool for 10.155.192.191

IP addresses on MSFC are:

VLAN 192 : 10.155.192.190

VLAN 194 : 10.155.194.191

Anyone has an idea?

Thanks

[thisisshanky]

Are these all class C subnet masks ?

Have you defined the scopes properly?. To start with I would like to take a look at your DHCP configs as well as interface vlan configs for vlans 194 and 192..

[nmorelli]

Hi, all the subnets are /23 (255.255.254.0)

It seems that all scopes are defined OK because I can get right IP addresses from vlan 194 and if I delete lease entry also from 192.

I send to you the Interface vlan configs as soon as possible.

Thank you.

[nmorelli]

Hi,

here's the config:

interface Vlan192

ip address 10.155.192.191 255.255.254.0

ip helper-address 10.155.201.21

no ip redirects

standby 192 priority 210 preempt

standby 192 ip 10.155.192.2

!

interface Vlan194

ip address 10.155.194.191 255.255.254.0

ip helper-address 10.155.201.21

no ip redirects

standby 194 priority 200 preempt

standby 194 ip 10.155.194.2

[paddyxdoyle]

Hi,

Your Cisco config looks fine.

I belive you need to be using superscopes on your DHCP server for it to assign address to hosts from multiple network IDs

You can also use netmon on the DHCP server to gather some network traces of the DHCP pakcets or create an access-list on the MSFC similar to

access-list 187 permit udp any any eq bootps

access-list 187 permit udp any any eq bootpc

debug ip packet detail 187

You may need to turn off CEF on your VLAN interfaces to see the results

HTH

PD

[nmorelli]

Hi, you are the best!!!

I solved the problem I created a superscope for each vlan and now works fine.

Thank you very mutch.

[paddyxdoyle]

no problem :)

Rgds

Paddy