DHCP not working

darren-carr · ‎02-02-2009

Hi guys,

There has been a need in our business to create a seperate VLAN for development work.

The vlan is vlan 20.

We have two Layer 3 switches doing onter-vlan routing.

We have a DHCP server on 192.168.2.1 and 192.168.2.2

I have defined the VLAN 20 on the L3 switches as 192.168.20.2 and 192.168.20.2 (HSRP) with the virtual gateway of 192.168.20.1 as the gateway for the clients.

I have also defined the IP helper on the vlans ip helper-address 192.168.2.1 and 192.168.2.2

I have used VTP to push this out to the remaining switches and this has worked.

However when I place a PC in this VLAN it is unable to contact the DHCP server for an address.

I have a W2K-2003 server as the DHCP server, have defined the scope, etc.

What am I missing? Thanks

mahmoodmkl · ‎02-02-2009

Hi

I have defined the VLAN 20 on the L3 switches as 192.168.20.2 and 192.168.20.2 (HSRP) with the virtual gateway of 192.168.20.1 as the gateway for the clients.

Can u confrim the other IP address in the HSRP group is it the same on both the switches..?

Can u verify weather spanning-tree portfast in configured under the vlan SVI.

Thanks

Mahmood

darren-carr · ‎02-02-2009

Hi Mahmood

On switch 2 the standby ip is 192.168.20.1 and it is the same on switch 3

On switch 2 the VLAN 20 IP address is 192.168.20.2 and on switch 3 the ip address is 192.168.20.3

One thing I have noticed is when I execute the sh standby on the switches both are showing as active?? Maybe this is causing the problem? I also cannot ping 192.168.20.2... the configs are exactly the same as they are for two other VLANs that are working?

darren-carr · ‎02-02-2009

Hi,

Here is my HSRP config for the VLAN followed by its current state on both switches

SW003

=========================================

interface Vlan20

description EXTERNAL CONTRACTOR vlan

ip address 192.168.20.3 255.255.255.0

standby 1 ip 192.168.20.1

standby 1 priority 105

standby 1 preempt delay minimum 60

end

SW002

=========================================

interface Vlan20

description EXTERNAL CONTRACTOR vlan

ip address 192.168.20.2 255.255.255.0

standby 1 ip 192.168.20.1

standby 1 preempt

end

HSRP STATUS SW003

=========================================

Vlan20 - Group 1

State is Active

14 state changes, last state change 00:05:47

Virtual IP address is 192.168.20.1

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 3 sec, hold time 10 sec

Next hello sent in 0.861 secs

Preemption enabled, delay min 60 secs

Active router is local

Standby router is unknown

Priority 105 (configured 105)

IP redundancy name is "hsrp-Vl20-1" (default)

SW002

=========================================

SW002#SH STANDby

Vlan20 - Group 1

State is Active

5 state changes, last state change 00:06:00

Virtual IP address is 192.168.20.1

Active virtual MAC address is 0000.0c07.ac01

Local virtual MAC address is 0000.0c07.ac01 (v1 default)

Hello time 3 sec, hold time 10 sec

Next hello sent in 0.165 secs

Preemption enabled

Active router is local

Standby router is unknown

Priority 100 (default 100)

IP redundancy name is "hsrp-Vl20-1" (default)

Thanks for any help

Darren

mahmoodmkl · ‎02-02-2009

Hi

It seems the switches are not able to exchange the hello packets.

Look in to cabling issues or u have a STP blocked port .

Thanks

Mahmood

darren-carr · ‎02-02-2009

Hi Mahmood,

It is very odd as other vlans with the same configuration on both switches are working? How do you diagnose a blocked port in a VLAN???

Thanks Darren

darren-carr · ‎02-02-2009

Also Mahmood I found this..

Not sure why this is the VLAN20 state

SW003#sh ip int br

Interface IP-Address OK? Method Status Protocol

Vlan1 192.168.2.251 YES NVRAM up up

Vlan20 192.168.20.3 YES manual up up

Vlan40 192.168.40.3 YES NVRAM up up

Vlan60 192.168.60.3 YES NVRAM administratively down down

Vlan70 192.168.70.3 YES NVRAM up up

mahmoodmkl · ‎02-02-2009

HI

Can u post the sh ip int bri from SW4 and sh vlan.

Thanks

Mahmood

darren-carr · ‎02-02-2009

Please see attached