dhcp snooping on Cisco C9600

[M_Neman]

Hello everyone, 

sorry for my english but i try my best to describe the situation, your help would be appreciated.

Access Switch<-->Distribution-Switch<-->DC-Switch--->DHCP Server

                                                                  |----------->PXE Server

our DHCP Server (vlan 4) is connected to DC-Switch and also PXE Sever (Vlan 10) connected to DC-Switch.

both IP (dhcp and pxe) are configured as helper-adresses on SVI Interfaces.

we have implemented dhcp snooping globally but not on the vlan 4. so everything works fine but pxe doesnt work.

i have disabled dhcp snooping also for vlan 10 and pxe works as well.

i have captured both traffic on both links but i dont see no where that the traffic for vlan 10 is being dropped.

my question is, i am sure that the pxe traffic was droped because of the dhcp snooping on vlan 10, what debug commonds can run to see the dchp discover packets or DHCP Offer packets from PXE Server are being dropped on the DC-Switch?

Thanks,

Mohammad

[MHM Cisco World]

I think it bug 

https://bst.cisco.com/bugsearch/bug/CSCvv24289?rfs=qvlogin

MHM

[M_Neman]

Thanks for your reply, 

But it isn't a bug, I just want to run some debug commands to find out where the packet is being dropped, on Distri switch or on DC switch ?

[MHM Cisco World]

I send you PM check it

MHM

[David Ruess]

Hello,

You could try to run a monitor capture command on the interface the PXE traffic will be seen from and export that into Wireshark. From there you may be able to see the traffic.

-David