Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 58)

Static ARP entry support (Continued) TABLE 6
Default maximum Configurable minimum Configurable maximum
ICX 6430 and ICX 6450 devices
256 64 1024
ICX 6610
512 512 6000
Enabling learning gratuitous ARP
Learning gratuitous ARP enables Brocade Layer 3 devices to learn ARP entries from incoming
gratuitous ARP packets from the hosts which are directly connected. This help achieve faster
convergence for the hosts when they are ready to send traffic.
A new ARP entry is created when a gratuitous ARP packet is received. If the ARP is already existing,
it will be updated with the new content.
To enable IP ARP learn gratuitous ARP, enter commands such as the following:
Brocade (config)# ip arp learn-gratuitous-arp
Brocade (config)# no ip arp learn-gratuitous-arp
Syntax: [no] ip arp learn-gratuitous-arp
The no form of the command disables learn gratuitous ARP from the device.
Use show run command to see whether ARP is enabled or disabled. Similarly, use show arp
command to see the newly learnt ARP entries.
ARP Packet Validation
Validates ARP Packets to avoid traffic interruption or loss.
To avoid traffic interruption or loss, ARP Packet Validation allows the user to detect and drop ARP
packets that do not pass the ARP validation process. ARP Packet Validation is disabled by default and
can be enabled at the global configuration level. This functionality can be configured for the destination
MAC address, the IP address and the source MAC address or with a combination of these
parameters. The Ethernet header contains the destination MAC address and source MAC address,
while the ARP packet contains the sender hardware address and target hardware address.
Follow these steps to perform checks on the incoming ARP Packets.
1. Enter the global configuration mode.
2. Run the ip arp inspection validate [dst-mac | ip | src-mac] command to perform a check on any
incoming ARP packets. Use one of the following parameters to run the validation check.
• dst-mac
The destination MAC address in the Ethernet header must be the same as the target hardware
address in the ARP body. This validation is performed for the ARP response packet. When the
destination MAC address validation is enabled, the packets with different MAC addresses are
classified as invalid and are dropped.
• src-mac
ARP Packet Validation
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