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By default, the AR1200-S checks the source and destination MAC addresses of all ARP packets.
If an ARP packet has an all-0 source or destination MAC address, the AR1200-S discards the
ARP packet.
Generally, the Ethernet header and ARP header of an ARP packet contain the same source MAC
address. If the two headers contain different source MAC addresses, the ARP packet may be an
attack packet. To protect the AR1200-S from ARP attacks, configure the AR1200-S to check
consistency of source MAC addresses in Ethernet and ARP headers of ARP packets.
Procedure
Step 1
Run:
system-view
The system view is displayed.
Step 2
Run:
arp anti-attack packet-check sender-mac
The AR1200-S is configured to check consistency of MAC addresses in Ethernet and ARP
headers of ARP packets.
By default, the AR1200-S does not check consistency of source MAC addresses in Ethernet and
ARP headers of ARP packets.
----End
6.4.4 Configuring ARP Gateway Anti-collision
If an attacker sends an ARP packet with the source IP address as the gateway address, ARP
entries in a VLAN are modified incorrectly. ARP gateway anti-collision can solve this problem.
Procedure
Step 1
Run:
system-view
The system view is displayed.
Step 2
Run:
arp anti-attack gateway-duplicate enable
ARP gateway anti-collision is enabled.
After ARP gateway anti-collision is enabled, the AR1200-S generates ARP anti-collision entries
and discards packets with the same source MAC address in the Ethernet header in a period of
time. This can prevent ARP packets with a bogus gateway address from being broadcast in a
VLAN.
----End
6.4.5 Configuring the AR1200-S to Send Gratuitous ARP Packets
By configuring the AR1200-S to send gratuitous ARP packets, the AR1200-S can send user
packets to the correct gateway and prevent malicious attackers from intercepting these packets.
Huawei AR1200-S Series Enterprise Routers
Configuration Guide - Security
6 ARP Security Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
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