Logging Of Dropped Packets; Default Dynamic Arp Inspection Configuration - Cisco Catalyst 2960 Software Configuration Manual

Chapter 22 Configuring Dynamic ARP Inspection

Logging of Dropped Packets

When the switch drops a packet, it places an entry in the log buffer and then generates system messages
on a rate-controlled basis. After the message is generated, the switch clears the entry from the log buffer.
Each log entry contains flow information, such as the receiving VLAN, the port number, the source and
destination IP addresses, and the source and destination MAC addresses.
You use the ip arp inspection log-buffer global configuration command to configure the number of
entries in the buffer and the number of entries needed in the specified interval to generate system
messages. You specify the type of packets that are logged by using the ip arp inspection vlan logging
global configuration command. For configuration information, see the
section on page
Configuring Dynamic ARP Inspection
•
•
•
•
•
•
•

Default Dynamic ARP Inspection Configuration

Table 22-1
Table 22-1
Feature
Dynamic ARP inspection
Interface trust state
Rate limit of incoming ARP packets
ARP ACLs for non-DHCP environments
Validation checks
OL-26520-01
22-13.
Default Dynamic ARP Inspection Configuration, page 22-5
Dynamic ARP Inspection Configuration Guidelines, page 22-6
Configuring Dynamic ARP Inspection in DHCP Environments, page 22-7
environments)
Configuring ARP ACLs for Non-DHCP Environments, page 22-9
environments)
Limiting the Rate of Incoming ARP Packets, page 22-11
Performing Validation Checks, page 22-12
Configuring the Log Buffer, page 22-13
shows the default dynamic ARP inspection configuration.
Default Dynamic ARP Inspection Configuration
Catalyst 2960 and 2960-S Switches Software Configuration Guide, Release 15.0(1)SE
Configuring Dynamic ARP Inspection
"Configuring the Log Buffer"
(required in non-DHCP
(optional)
(optional)
(optional)
Default Setting
Disabled on all VLANs.
All interfaces are untrusted.
The rate is 15 pps on untrusted interfaces, assuming that
the network is a switched network with a host
connecting to as many as 15 new hosts per second.
The rate is unlimited on all trusted interfaces.
The burst interval is 1 second.
No ARP ACLs are defined.
No checks are performed.
(required in DHCP
22-5