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6.1 ARP Security Overview
This section describes the principle of ARP security.
ARP Attacks
ARP-oriented attacks include ARP spoofing attacks and ARP flood attacks.
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ARP spoofing attack: An attacker sends a large number of bogus ARP packets to modify
ARP entries of network devices. As a result, packet forwarding is affected. Attackers initiate
ARP spoofing attacks by using either of the following methods:
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Forging user host IP addresses
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Forging gateway addresses
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ARP flood attack: An attacker sends a large number of bogus ARP Request packets or
gratuitous ARP packets. The AR1200-S is busy with ARP processing for a long period and
cannot process other services. The rate of ARP packets may exceed the limit and ARP
entries may overflow. As a result, ARP entries of valid users cannot be buffered and packet
forwarding is affected. ARP flood attacks are classified into the following types:
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ARP Denial of Service (DoS) attacks
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ARP buffer overflow attacks
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ARP-based network scanning attacks
ARP Security
ARP security ensures security and robustness of network devices by filtering out untrusted ARP
packets, checking the binding table of ARP packets, and defending against ARP gateway
conflicts.
6.2 ARP Security Supported by the AR1200-S
The ARP security features supported by the AR1200-S include limitation of ARP entry learning,
ARP anti-spoofing, defense against ARP gateway attacks, source address-based ARP packet
suppression, source address-based ARP Miss packet suppression and ARP packet rate limit.
ARP Entry Limiting
You can configure strict ARP learning so that the AR1200-S can learn only the response
messages of the ARP requests sent locally.
You can set the maximum number of ARP entries that can be dynamically learned by an
interface. This prevents malicious use of ARP entries and ensures that the AR1200-S can learn
the ARP entries of authorized users.
ARP Anti-spoofing
ARP spoofing means that attackers use ARP packets sent by authorized users to construct bogus
ARP packets and modify ARP entries on the gateway. As a result, the authorized users are
disconnected from the network.
The AR1200-S can prevent ARP spoofing by using the following methods:
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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