Configuring Advanced Threat Protection

Dynamic IP Lockdown

Dynamic IP lockdown only filters packets in VLANs that are enabled for DHCP snooping. In order for Dynamic IP lockdown to work on a port, the port must be configured for at least one VLAN that is enabled for DHCP snooping.

To enable DHCP snooping on a VLAN, enter the dhcp-snooping vlan [vlan-id-range] command at the global configuration level or the dhcp-snoopingcommand at the VLAN configuration level.

Dynamic IP lockdown is not supported on a trusted port. (However, note that the DHCP server must be connected to a trusted port when DHCP snooping is enabled.)

By default, all ports are untrusted. To remove the trusted configuration from a port, enter the no dhcp-snooping trust <port-list> command at the global configuration level.

For more information on how to configure and use DHCP snooping, see “DHCP Snooping” on page 8-4.

After you enter the ip source-lockdowncommand (enabled globally with the desired ports entered in <port-list>), the dynamic IP lockdown feature remains disabled on a port if any of the following conditions exist:

If DHCP snooping has not been globally enabled on the switch.

If the port is not a member of at least one VLAN that is enabled for DHCP snooping.

If the port is configured as a trusted port for DHCP snooping.

Dynamic IP lockdown is activated on the port only after you make the following configuration changes:

Enable DHCP snooping on the switch.

Configure the port as a member of a VLAN that has DHCP snooping enabled.

Remove the trusted-port configuration.

You can configure dynamic IP lockdown only from the CLI; this feature cannot be configured from the web management or menu interface.

If you enable dynamic IP lockdown on a port, you cannot add the port to a trunk.

Dynamic IP lockdown must be removed from a trunk before the trunk is removed.

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