Cisco Systems 3560 Manual De Usuario

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Catalyst 3560 Switch Software Configuration Guide
OL-8553-06
Chapter 21      Configuring DHCP Features and IP Source Guard
Configuring IP Source Guard
These sections contain this information:
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Source IP Address Filtering
When IP source guard is enabled with this option, IP traffic is filtered based on the source IP address. 
The switch forwards IP traffic when the source IP address matches an entry in the DHCP snooping 
binding database or a binding in the IP source binding table. 
When a DHCP snooping binding or static IP source binding is added, changed, or deleted on an interface, 
the switch modifies the port ACL using the IP source binding changes, and re-applies the port ACL to 
the interface. 
If you enable IP source guard on an interface on which IP source bindings (dynamically learned by 
DHCP snooping or manually configured) are not configured, the switch creates and applies a port ACL 
that denies all IP traffic on the interface. If you disable IP source guard, the switch removes the port ACL 
from the interface.
Source IP and MAC Address Filtering
When IP source guard is enabled with this option, IP traffic is filtered based on the source IP and MAC 
addresses. The switch forwards traffic only when the source IP and MAC addresses match an entry in 
the IP source binding table.
When IP source guard with source IP and MAC address filtering is enabled, the switch filters IP and 
non-IP traffic. If the source MAC address of an IP or non-IP packet matches a valid IP source binding, 
the switch forwards the packet. The switch drops all other types of packets except DHCP packets.
The switch uses port security to filter source MAC addresses. The interface can shut down when a 
port-security violation occurs.
Configuring IP Source Guard
These sections contain this configuration information:
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Default IP Source Guard Configuration
By default, IP source guard is disabled.