Cisco Catalyst 3750-E User Manual

23-5
Catalyst 3750-E and 3560-E Switch Software Configuration Guide
OL-9775-08
Chapter 23 Configuring Dynamic ARP Inspection
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 “Configuring the Log Buffer”
section on page 23-13.
Configuring Dynamic ARP Inspection
• Default Dynamic ARP Inspection Configuration, page 23-5
• Dynamic ARP Inspection Configuration Guidelines, page 23-6
• Configuring Dynamic ARP Inspection in DHCP Environments, page 23-7 (required in DHCP
environments)
• Configuring ARP ACLs for Non-DHCP Environments, page 23-9 (required in non-DHCP
environments)
• Limiting the Rate of Incoming ARP Packets, page 23-11 (optional)
• Performing Validation Checks, page 23-12 (optional)
• Configuring the Log Buffer, page 23-13 (optional)
Default Dynamic ARP Inspection Configuration
Ta b l e 23-1 Default Dynamic ARP Inspection Configuration
Feature Default Setting
Dynamic ARP inspection Disabled on all VLANs.
Interface trust state All interfaces are untrusted.
Rate limit of incoming ARP packets The rate is 15 pps on untrusted interfaces, assuming that the
ne
twork 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.
ARP ACLs for non-DHCP
e
nvironments
No ARP ACLs are defined.
Validation checks No checks are performed.

Cisco Catalyst 3750-E Specifications

General

Series	Catalyst 3750-E
Switching Capacity	32 Gbps
Stacking Bandwidth	32 Gbps
StackWise Plus	Yes
Layer Support	Layer 3
MAC Address Table Size	12, 000 entries
RAM	256 MB
Flash Memory	64 MB
Memory	256 MB DRAM, 64 MB Flash
Operating Temperature	32 to 113°F (0 to 45°C)
Ports	48 10/100/1000 Ethernet ports
Form Factor	Rack-mountable
Jumbo Frame Support	Yes
Input Voltage	100 to 240 VAC
Storage Temperature	-25 to 70 °C
Relative Humidity	10 to 90% non-condensing