21-17
Catalyst 3750 Switch Software Configuration Guide
78-16180-02
Chapter 21 Configuring DHCP Features and IP Source Guard
Configuring IP Source Guard
Configuration Guidelines
These are the configuration guides for IP source guard:
• You can configure static IP bindings only on nonrouted ports. If you enter the ip source binding
ip-address mac-address vlan vlan-id 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 a VLAN, DHCP snooping must be
enabled on the access VLAN to which the interface belongs.
• 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.
Note If IP source guard is enabled and you enable or disable DHCP snooping on a VLAN on the
trunk interface, the switch might not properly filter traffic.
• When IP source guard with source IP and MAC address filtering is enabled, DHCP snooping and
port security must be enabled on the interface.
• IP source guard is not supported on EtherChannels.
• You can enable this feature when Virtual Routing Function (VRF) Lite or 802.1x port-based
authentication is enabled.
• If the number of ternary content addressable memory (TCAM) entries exceeds the maximum
available, the CPU usage increases.
Enabling IP Source Guard
Beginning in privileged EXEC mode, follow these steps to enable and configure IP source guard on an
interface.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
interface interface-id Enter interface configuration mode, and specify the interface to be
configured.
Step 3
ip verify source
or
ip verify source port-security
Enable IP source guard with source IP address filtering.
Enable IP source guard with source IP and MAC address filtering.
Step 4
exit Return to global configuration mode.
Step 5
ip source binding mac-address vlan
vlan-id ip-address inteface interface-id
Add a static IP source binding.
Enter this command for each static binding.
Step 6
end Return to privileged EXEC mode.
Step 7
show ip verify source [interface
interface-id]
Display the IP source guard configuration for all interfaces or for a
specific interface.
To Next Page
Loading...
Need help?
General