[c-nsp] dhcp snooping

[Kyle Evans]

I have a network topology like this:


snoopSwitch-------------Router----------------distSwitch---------------userSwitch
 			  |
			  |
			  |
DHCP Server------------serverSwitch



1. All uplinks are Fa0/1

2. snoopSwitch, distSwitch, and userSwitch have vlans 571 and 832

3. serverSwitch does NOT have vlans 571 or 832

4. Router has vlan interfaces for all vlans and helper addresses on each
vlan interface that point to DHCP Server.

5. snoopSwitch has dhcp snooping enabled with the following config:

ip dhcp snooping
ip dhcp snooping vlan 832
no ip dhcpd snooping information option

interface FastEthernet0/1
 switchport trunk encap dot1q
 switchport mode trunk
 ip dhcp snooping trust
 speed 100
 duplex full


6. No other devices have dhcp snooping enabled in any fashion.


Under this setup, a user plugged into a port on userSwitch that is in
vlan 571 can no longer receive from the DHCP Server.  Is this correct
behavior?

Does dhcp snooping have to be set up on every device in the network for
it to work right?  Or does it have to be set up on every device with a
certain vlan?  Or is it possible some way to just set it up for one vlan
on one single switch?


Kyle