Wired Intelligent Edge

Hi Have been trying to get dhcp-snooping going but clients will not get an IP 

this is what I apply

dhcp-snooping
dhcp-snooping vlan 114
dhcp-snooping vlan 214

interface Trk1
dhcp-snooping trust

Do I have to trust the interfaces in the trunk also ?

trunk 1/47,7/47 trk1 lacp

Thank you

you know DHCP snooping is different from DHCP relay.

are you trying to configure DHCP relay or helper address so that the clients anget IP address from the DHCP server that is not on the same VLAN?

Yes , I am not trying to configure DHCP relay , all our helper address are on our core , I am just trying to lock donw DHCP request from trusted up link ports, 

But When I have dhcp-snooping enabled and the truck trusted , I get no IP , Im wondering if I have to also trust the interfaces in the trunk.

Pino

Trusting the trunk interface would be enough.

Does it work when you disable snooping?

Yes as soon as I disable snooping dhcp works fine for clients.

When dhcp is active, do you see the the trk1 interface as trusted?

is Trk1 really the correct and only uplink?

SW01-SER# show dhcp-snooping

DHCP Snooping Information

DHCP Snooping : Yes
Enabled VLANs : 1-4094
Verify MAC address : Yes
Option 82 untrusted policy : drop
Option 82 insertion : Yes
Option 82 remote-id : mac
Store lease database : Not configured
Rate-Limit (PPS) : 100

Max Current Bindings
Port Trust Bindings Static Dynamic
----- ----- -------- ----------------
1/1 No - - 1
1/2 No - - 1

Trk1 Yes - - -

also please share the output of:

show dhcp-snooping

show dhcp-snooping stats

show dhcp-snooping binding

Hi , here is what I have configured

Duffy-Main-MDF(config)# sho dhcp-snooping

DHCP Snooping Information

DHCP Snooping : Yes
Enabled VLANs : 113 123 213
Verify MAC address : No
Option 82 untrusted policy : drop
Option 82 insertion : Yes
Option 82 remote-id : mac
Store lease database : Not configured
Rate-Limit (PPS) : 100

Max Current Bindings
Port Trust Bindings Static Dynamic
----- ----- -------- ----------------
Trk1 Yes - - -

Ports
1/1-1/46,1/48,2/1-2/48,3/1-3/48,4/1-4/48,5/1-5/48,6/1-6/48,7/1-7/48,8/1-8/46,8/
48 are untrusted

Duffy-Main-MDF(config)# sho dhcp-snooping stats

Packet type Action Reason Count
----------- ------- ---------------------------- ---------
server forward from trusted port 0
client forward to trusted port 341
server drop received on untrusted port 0
server drop unauthorized server 0
client drop destination on untrusted port 0
client drop untrusted option 82 field 0
client drop bad DHCP release request 0
client drop failed verify MAC check 0
client drop failed on max-binding limit 0

Duffy-Main-MDF(config)# sho dhcp-snooping binding

MacAddress IP VLAN Interface Time Left
----------------- --------------- ---- --------- ---------

The funny thing is I sometimes can get a laptop to work but if I plug in a IPphone or wap they do not get an ip as soon as I disable snooping they come right up.

Hi All, I was able to get this working , I had to disable option 82 on our stacks, I'm not sure what it does but I came across another post where it solved a similar issue, and I tried it and it worked !

Thank you for all the help

Can you see anything about DHCP packets being dropped in the switch log?