Ip dhcp snooping trust, Ip dhcp snooping trust (666) – Microsens MS453490M Management Guide User Manual

Page 666

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C

HAPTER

25

| General Security Measures

DHCP Snooping

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When the DHCP snooping is globally disabled, DHCP snooping can still

be configured for specific VLANs, but the changes will not take effect

until DHCP snooping is globally re-enabled.

When DHCP snooping is globally enabled, configuration changes for

specific VLANs have the following effects:

If DHCP snooping is disabled on a VLAN, all dynamic bindings

learned for this VLAN are removed from the binding table.

E

XAMPLE

This example enables DHCP snooping for VLAN 1.

Console(config)#ip dhcp snooping vlan 1

Console(config)#

R

ELATED

C

OMMANDS

ip dhcp snooping (661)

ip dhcp snooping trust (666)

ip dhcp snooping

trust

This command configures the specified interface as trusted. Use the no

form to restore the default setting.

S

YNTAX

[no] ip dhcp snooping trust

D

EFAULT

S

ETTING

All interfaces are untrusted

C

OMMAND

M

ODE

Interface Configuration (Ethernet, Port Channel)

C

OMMAND

U

SAGE

A trusted interface is an interface that is configured to receive only

messages from within the network. An untrusted interface is an

interface that is configured to receive messages from outside the

network or fire wall.

Set all ports connected to DHCP servers within the local network or fire

wall to trusted, and all other ports outside the local network or fire wall

to untrusted.

When DHCP snooping ia enabled globally using the

ip dhcp snooping

command, and enabled on a VLAN with

ip dhcp snooping vlan

command, DHCP packet filtering will be performed on any untrusted

ports within the VLAN according to the default status, or as specifically

configured for an interface with the no ip dhcp snooping trust

command.

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