No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

CX11x, CX31x, CX710 (Earlier Than V6.03), and CX91x Series Switch Modules V100R001C10 Configuration Guide 12

The documents describe the configuration of various services supported by the CX11x&CX31x&CX91x series switch modules The description covers configuration examples and function configurations.
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Applications

Applications

This section describes the applicable scenario of ARP Security.

Defense Against ARP Flood Attacks

As shown in Figure 12-42, hosts connect to the gateway to access the Internet using SwitchA and SwitchB. If a large number of ARP packets are broadcast on the network, the device cannot process other services due to CPU overload. An ARP flood occupies high bandwidth and leads to network congestion, affecting network communication.

Figure 12-42 Defending against ARP flood attacks

To avoid the preceding problems, deploy ARP flood defense functions on the gateway, including rate limit on ARP packets, rate limit on ARP Miss messages, gratuitous ARP packet discarding, strict ARP learning, and ARP entry limit.

  • After rate limit on ARP packets is deployed, the gateway collects statistics on received ARP packets. If the number of ARP packets received within a specified period exceeds the threshold (the maximum number of ARP packets), the gateway discards the excess ARP packets to prevent CPU overload.

  • After rate limit on ARP Miss messages is deployed, the gateway collects statistics on ARP Miss messages. If the number of ARP Miss messages generated within a specified period exceeds the threshold (the maximum number of ARP Miss messages), the gateway discards the IP packets triggering the excess ARP Miss messages. This prevents CPU overload when the gateway processes a large number of IP packets with unresolvable IP addresses.

  • After gratuitous ARP packet discarding is deployed, the gateway discards gratuitous ARP packets, reducing CPU load.

  • After strict ARP learning is deployed, the gateway learns only the ARP Reply packets in response to the ARP Request packets sent by itself. This prevents ARP entries on the gateway from being exhausted when the gateway processes many ARP packets.

  • After ARP entry limit is deployed, the gateway limits the number of ARP entries dynamically learned by each interface. When the number of the ARP entries dynamically learned by an interface reaches the maximum number, no dynamic entry can be added. This prevents ARP entries from being exhausted when a host connected to the interface attacks the gateway.

Defense Against ARP Spoofing Attacks

As shown in Figure 12-43, UserA, UserB, and UserC use Switch to connect to the gateway to access the Internet.

Generally, when UserA, UserB, and UserC go online and exchange ARP packets, ARP entries are created on UserA, UserB, UserC, and the gateway. At the same time, an attacker can send bogus ARP packets to UserA, UserB, UserC, or the gateway in the broadcast domain to modify ARP entries, intercept information, and interrupt communication.

Figure 12-43 Defending against ARP spoofing attacks

To avoid the preceding problems, deploy ARP spoofing defense functions on the gateway, including rate ARP entry fixing, gratuitous ARP packet discarding, and strict ARP learning.

  • After ARP entry fixing is deployed and the gateway learns an ARP entry for the first time, the gateway does not change the ARP entry, only updates part of the entry, or sends a unicast ARP Request packet to check validity of the ARP packet for updating the entry. This function prevents ARP entries from being modified by bogus ARP packets.

  • After gratuitous ARP packet discarding is deployed, the gateway discards gratuitous ARP packets, preventing ARP entries from being modified by bogus ARP packets.

  • After strict ARP learning is deployed, the gateway learns only the ARP Reply packets in response to the ARP Request packets sent by itself. This prevents ARP entries from being modified by bogus ARP packets.

Translation
Download
Updated: 2019-08-09

Document ID: EDOC1000041694

Views: 59164

Downloads: 3623

Average rating:
This Document Applies to these Products
Related Version
Related Documents
Share
Previous Next