Chapter 25 IP Source Guard
•Use the ARP Inspection Status screen (Section 25.6 on page 233) to look at the current list of MAC address filters that were created because the Switch identified an unauthorized ARP packet.
•Use the ARP Inspection VLAN Status screen (Section 25.7 on page 234) to look at various statistics about ARP packets in each VLAN.
•Use the ARP Inspection Log Status screen (Section 25.8 on page 235) to look at log messages that were generated by ARP packets and that have not been sent to the syslog server yet.
•Use the ARP Inspection Configure screen (Section 25.9 on page 236) to enable ARP inspection on the Switch. You can also configure the length of time the Switch stores records of discarded ARP packets and global settings for the ARP inspection log.
•Use the ARP Inspection Port Configure screen (Section 25.9.1 on page 238) to specify whether ports are trusted or untrusted ports for ARP inspection.
•Use the ARP Inspection VLAN Configure screen (Section 25.9.2 on page 240) to enable ARP inspection on each VLAN and to specify when the Switch generates log messages for receiving ARP packets from each VLAN.
25.1.2What You Need to Know
The Switch builds the binding table by snooping DHCP packets (dynamic bindings) and from information provided manually by administrators (static bindings).
IP source guard consists of the following features:
•Static bindings. Use this to create static bindings in the binding table.
•DHCP snooping. Use this to filter unauthorized DHCP packets on the network and to build the binding table dynamically.
•ARP inspection. Use this to filter unauthorized ARP packets on the network.
If you want to use dynamic bindings to filter unauthorized ARP packets (typical implementation), you have to enable DHCP snooping before you enable ARP inspection.
25.2 IP Source Guard
Use this screen to look at the current bindings for DHCP snooping and ARP inspection. Bindings are used by DHCP snooping and ARP inspection to distinguish between authorized and unauthorized packets in the network. The Switch learns the bindings by snooping DHCP packets (dynamic bindings) and from information
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