H3C Technologies H3C SecPath F1000-E - Manual (Page 505)

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Table 3 Configuration items of periodic sending of gratuitous ARP packets
Item Description
Sending Interface
Specify an interface and interval for periodically sending gratuitous
ARP packets.
Select an interface from the Standby Interface list, set its sending
interval, and then click << to add it to the Sending Interface list box.
To delete the combination of an interface and its sending interval, select
it from the Sending Interface list and click >>.
IMPORTANT:
z The device supports up to 1024 interfaces to send gratuitous ARP
packets periodically.
z With this feature enabled, an interface can periodically send
gratuitous ARP packets only after it is assigned with an IP address
and the link comes up.
z If a sending interval is modified, the setting takes effect at the next
interval.
z If a number of interfaces are enabled with this feature, or each
interface has a large amount of secondary IP addresses, or the
sending intervals are very short in the scenario where the above
two conditions exist at the same time, the frequency at which
gratuitous ARP packets are sent may be far lower than your
expectation.
ARP Automatic Scanning and Fixed ARP
Introduction to ARP Automatic Scanning and Fixed ARP
ARP automatic scanning is usually used together with the fixed ARP feature.
• With the ARP automatic scanning feature enabled, the device scans the LAN for neighbors by
sending ARP requests, and thereby obtains the MAC addresses of the neighbors and adds
dynamic ARP entries.
• With the fixed ARP feature, the device can convert dynamic ARP entries (including those added by
ARP automatic scanning) into static ones, thus preventing attackers from modifying ARP entries
effectively.
NOTE:
These two features are recommended to be used in small-sized and stable networks, such as an Internet
café.
Configuring ARP Automatic Scanning
NOTE:
•
It is not recommended to perform other operations when ARP automatic scanning is in progress.
• ARP automatic scanning may take a long time. You can abort the scanning by clicking Interrupt on the
ARP scan page.