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Catalyst 6500 Series Switch Command Reference—Release8.4
OL-6244-01
Chapter2 Catalyst 6500 Series Switch and ROM Monitor Commands set port dhcp-snooping
set port dhcp-snooping
To enable DHCP trust and IP Source Guard on a per-port basis, use the set port dhcp-snooping
command.
set port dhcp-snooping mod/ports {trust | source-guard} {enable | disable}
Syntax Description
Defaults Trust and source-guard are disabled.
Command Types Switch command.
Command Modes Privileged.
Usage Guidelines If you enter the set port dhcp-snooping mod/ports trust disable command, the DHCP snooping feature
performs checks on packets coming from the ports that you specify. If you enter the enable keyword, th e
feature trusts the packets from those ports and does not perform checks.
If you enter the set port dhcp-snooping mod/ports source-guard enable command, the IP address es
learned through DHCP snooping are the only source IP addresses a llowed on i ncomi n g tr affic. All
packets that contain other IP addresses are dropped. If a new binding i s added, the IP address associated
with that binding is added to the port. If a binding is de leted, the IP address associated with that binding
is removed from the port.
If DHCP snooping is disabled on a VLAN, the bindings for that VLAN are deleted.
If you enable IP Source Guard on a port, that port shoul d be untru st ed. Also , the sec ur ity ACL mode
should be port-based or merge-mode, and no PACLs should be on the port.
IP source guard is supported only on the PFC3 or later.
Examples This example shows how to enable DHCP trust on port 2 of module 2:
Console> (enable) set port dhcp-snooping 2/2 trust enable
Port(s) 2/2 state set to trusted for DHCP Snooping.
Console> (enable)
This example shows how to enable IP source-guard on port 2 of module 2:
Console> (enable) set port dhcp-snooping 2/2 source-guard enable
Enabling IP Source Guard on port(s) 2/2.
Console> (enable)
mod/ports Number of the module and port or multiple ports.
trust Specifies the trust feature.
source-guard Specifies the IP Source-Guard feature.
enable Enables the specified DHCP-Snooping feature.
disable Disables the specified DHCP-Snooping feature.