Configuring Arp Scanning And Fixed Arp; Configuration Restrictions And Guidelines; Configuration Procedure; Configuring Arp Gateway Protection - HPE FlexNetwork 7500 Series Security Configuration Manual

Configuring ARP scanning and fixed ARP

ARP scanning is typically used together with the fixed ARP feature in small-scale networks.
ARP scanning automatically creates ARP entries for devices in an address range. The device
performs ARP scanning in the following steps:
1. Sends ARP requests for each IP address in the address range.
2. Obtains their MAC addresses through received ARP replies.
3. Creates dynamic ARP entries.
Fixed ARP converts existing dynamic ARP entries (including those generated through ARP scanning)
to static ARP entries. This feature prevents ARP entries from being modified by attackers. Static
ARP entries can also be manually configured by the arp static command.

Configuration restrictions and guidelines

Follow these restrictions and guidelines when you configure ARP scanning and fixed ARP:
•
IP addresses in existing ARP entries are not scanned.
•
ARP scanning will take some time. To stop an ongoing scan, press Ctrl + C. Dynamic ARP
entries are created based on ARP replies received before the scan is terminated.
•
The arp fixup command is a one-time operation. You can use this command again to convert
the dynamic ARP entries learned later to static.
•
Due to the limit on the total number of static ARP entries, some dynamic ARP entries might fail
the conversion.
•
To delete a static ARP entry converted from a dynamic one, use the undo arp ip-address
[ vpn-instance-name ] command. Use the reset arp all command to delete all ARP entries or
the reset arp static command to delete all static ARP entries.

Configuration procedure

To configure ARP scanning and fixed ARP:
Step
1. Enter system view.
2. Enter interface view.
3. Trigger an ARP scanning.
4. Return to system view.
5. Convert existing dynamic ARP entries to
static ARP entries.

Configuring ARP gateway protection

Configure this feature on interfaces not connected with a gateway to prevent gateway spoofing
attacks.
When such an interface receives an ARP packet, it checks whether the sender IP address in the
packet is consistent with that of any protected gateway. If yes, it discards the packet. If not, it handles
the packet correctly.
Command
system-view
interface interface-type interface-number
arp scan [ start-ip-address to end-ip-address ]
quit
arp fixup
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