HP A5830 Series User Manual

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Task Remarks
prevention
Configuring ARP active acknowledgement
Optional.
Configure this function on gateways
(recommended).
Configuring ARP detection
Optional.
Configure this function on access
devices (recommended).
Configuring ARP automatic scanning and fixed
ARP
Optional.
Configure this function on gateways
(recommended).
Configuring ARP defense against IP packet attacks
If the device receives a large number of IP packets from a host addressed to unreachable destinations,
the following occur:
• The device sends a large number of ARP requests to the destination subnets. Therefore, the load of
the destination subnets increases.
• The device keeps trying to resolve destination IP addresses, which increases the load on the CPU.
To protect the device from IP packet attacks, you can enable the ARP source suppression function or ARP
black hole routing function.
If the packets have the same source address, you can enable the ARP source suppression function. With
the function enabled, you can set a threshold for the number of ARP requests that a sending host can
trigger in 5 seconds with packets with unresolvable destination IP addresses. When the number of ARP
requests exceeds that threshold, the device suppresses the host from triggering any ARP requests in the
following 5 seconds.
If the packets have various source addresses, you can enable the ARP black hole routing function. After
receiving an IP packet whose destination IP address cannot be resolved by ARP, the device with this
function enabled immediately creates a black hole route and simply drops all packets matching the route
during the aging time of the black hole route.
Configuring ARP source suppression
To do… Use the command… Remarks
1. Enter system view.
system-view —
2. Enable ARP source suppression.
arp source-suppression enable
Required
Disabled by default
3. Set the maximum number of packets with the
same source IP address but unresolvable
destination IP addresses that the device can
receive in 5 consecutive seconds.
arp source-suppression limit
limit-value
Optional
10 by default

HP A5830 Series Specifications

General

Brand	HP
Model	A5830 Series
Category	Switch
Language	English