06-26-2008 07:55 AM - edited 03-05-2019 11:51 PM
i cannot get DHCP snooping to work across 2 separate switches.
DHCP snooping is enabled on each VLAN and the DHCP server is located on switch 1 with the interface is trusted.
from switch 2 DHCP works okay when DHCP snooping is not enabled on switch 2.
once DHCP snooping is enabled on switch 2 it no longer works. i've tried trusting the trunk link to switch 1 but it still does not work
HELP!!
06-26-2008 08:05 AM
You need to apply trust on each end of the trunk as DHCP packets will travel both ways (Client requests and Server responses).
interface GigabitEthernet0/1
ip dhcp snooping trust
Andy
06-26-2008 12:14 PM
is the correct command at either end of the trunk; ip dhcp snooping trust?
as i have also read about the following command;
ip dhcp relay information trusted
06-26-2008 12:35 PM
use " ip dhcp snooping trust" on your uplink (trunks) ports as trusted
06-26-2008 12:44 PM
to setup dhcp snooping,
1, enable dhcp snooping globally " switch(config)#ip dhcp snooping"
2, enable dhcp option 82 to forward dhcp request packet to contain information on the switch port where it originated(optional) "switch(config)#ip dhcp snooping information option"
3, configure dhcp server interfaces or uplink ports as trusted " switch(config-if)#ip dhcp snooping trust"
4, enable dhcp snooping on specific vlans " switch(config)#ip dhcp snooping vlan (vlan number)
5, vertify the configuration " show ip dhcp snooping.
pls rate if this helps
06-27-2008 12:30 AM
In the global config you need:
(config)#ip dhcp snooping
AND
(config)#ip dhcp snooping vlan 1
On my switches if I don't issue both commands it doesn't work.
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