472
[DeviceB-vlan10] quit
After the configuration is completed, Device B forwards ARP broadcast requests from Host A to
Device A through the trusted interface Ten-GigabitEthernet 1/0/3. Host B cannot receive such
packets. Port isolation operates correctly.
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 Command
1.
Enter system view.
system-view
2.
Enter interface view.
interface
interface-type interface-number
3.
Trigger an ARP scanning.
arp scan
[
start-ip-address
to
end-ip-address
]
4.
Return to system view.
quit
5.
Convert existing dynamic ARP entries to
static ARP entries.
arp fixup
Configuring ARP gateway protection
Configure this feature on interfaces not connected with a gateway to prevent gateway spoofing
attacks.
Содержание FlexFabric 5940 SERIES
Страница 251: ...238 ...