Default Ip Source Guard Configuration; Ip Source Guard Configuration Guidelines; Enabling Ip Source Guard - Cisco Catalyst 2928 Software Configuration Manual

Configuring IP Source Guard

Default IP Source Guard Configuration

By default, IP source guard is disabled.

IP Source Guard Configuration Guidelines

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Enabling IP Source Guard

Begin in privileged EXEC mode.
Command
Step 1 configure terminal
Step 2 interface interface-id
Catalyst 2928 Switch Software Configuration Guide
19-16
You can configure static IP bindings only on nonrouted ports. If you enter the ip source binding
mac-address vlan vlan-id ip-address interface interface-id global configuration command on a
routed interface, this error message appears:
Static IP source binding can only be configured on switch port.
When IP source guard with source IP filtering is enabled on an interface, DHCP snooping must be
enabled on the access VLAN for that interface.
If you are enabling IP source guard on a trunk interface with multiple VLANs and DHCP snooping
is enabled on all the VLANs, the source IP address filter is applied on all the VLANs.
If IP source guard is enabled and you enable or disable DHCP snooping on a VLAN on the
Note
trunk interface, the switch might not properly filter traffic.
If you enable IP source guard with source IP and MAC address filtering, DHCP snooping and port
security must be enabled on the interface. You must also enter the ip dhcp snooping information
option global configuration command and ensure that the DHCP server supports option 82. When
IP source guard is enabled with MAC address filtering, the DHCP host MAC address is not learned
until the host is granted a lease. When forwarding packets from the server to the host, DHCP
snooping uses option-82 data to identify the host port.
When configuring IP source guard on interfaces on which a private VLAN is configured, port
security is not supported.
IP source guard is not supported on EtherChannels.
You can enable this feature when 802.1x port-based authentication is enabled.
If the number of ternary content addressable memory (TCAM) entries exceeds the maximum, the
CPU usage increases.
Purpose
Enter global configuration mode.
Specify the interface to be configured, and enter interface configuration
mode.
Chapter 19 Configuring DHCP Features and IP Source Guard Features
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