Access Control Lists

3-107

3
IP Address Type – Indicates an IPv4 address type.
Lease Time (Seconds) – The time for which this IP address is leased to the client.
Web – Click DHCP Snooping, DHCP Snooping Binding Information.
Figure 3-66 DHCP Snooping Binding Information
CLI – This example shows how to display the DHCP Snooping binding table entries.

IP Source Guard

IP Source Guard is a security feature that filters IP traffic on network interfaces
based on manually configured entries in the IP Source Guard table, or dynamic
entries in the DHCP Snooping table when enabled (see "Filtering IP Addresses for
Management Access" on page 3-99). IP source guard can be used to prevent traffic
attacks caused when a host tries to use the IP address of a neighbor to access the
network. This section describes commands used to configure IP Source Guard.
Note: Due to a chip limitation, IP source guard and Quality of Service (for IP-related
QoS) cannot be enabled at the same time.

Configuring Ports for IP Source Guard

Use the IP Source Guard Port Configuration page to set the filtering type based on
source IP address or source IP address and MAC address pairs.
IP Source Guard is used to filter traffic on an insecure port which receives messages
from outside the network or firewall, and therefore may be subject to traffic attacks
caused by a host trying to use the IP address of a neighbor.
Console#show ip dhcp snooping binding 4-138
MacAddress IpAddress Lease(sec) Type VLAN Interface
----------------- --------------- ---------- -------------------- ---- ---------
11-22-33-44-55-66 192.168.0.99 0 Dynamic 1 Eth 1/5
Console#