Cisco Cisco Identity Services Engine Software Manual Técnica

Device tracking adds an entry when:

it learns the new entry via DHCP snooping.

• 

it learns the new entry via an Address Resolution Protocol (ARP) request (reads the sender MAC
address and the sender IP address from the ARP packet). That functionality is sometimes called ARP
inspection, but it is not the same as Dynamic ARP Inspection (DAI). That feature is enabled by
default and cannot be disabled. It is also called ARP snooping, but debugs will not show it after
"debug arp snooping" is enabled. ARP snooping is enabled by default and cannot be disabled or
controlled.

• 

Device tracking removes an entry when there is no response for an ARP request (sending probe for each host
in the device tracking table, by default every 30 seconds).

ip dhcp excluded-address 192.168.0.1 192.168.0.240

ip dhcp pool POOL

   network 192.168.0.0 255.255.255.0

!

ip dhcp snooping vlan 1

ip dhcp snooping

ip device tracking

!

interface Vlan1

  ip address 192.168.0.2 255.255.255.0

ip route 0.0.0.0 0.0.0.0 10.48.66.1

!

interface FastEthernet0/1

  description PC

BSNS-3560-1# 

IP address       Client-ID/              Lease expiration        Type

                 Hardware address

192.168.0.241    0100.5056.994e.a1       Mar 02 1993 02:31 AM    Automatic

BSNS-3560-1# 

IP Device Tracking = Enabled

--------------------------------------------------------------

  IP Address     MAC Address       Interface          STATE   

--------------------------------------------------------------

192.168.0.241   0050.5699.4ea1 FastEthernet0/1        ACTIVE

DHCP snooping populates the binding table:

BSNS-3560-1#  

DHCP Snooping packet debugging is on

DHCP Snooping event debugging is on

DHCP server packet debugging is on.

DHCP server event debugging is on.

track:

  IP device-tracking redundancy events debugging is on