H3C Technologies H3C S12500 Series Switches - Manual (Page 104)

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Optimizing IP performance
A customized configuration can help optimize overall IP performance. This chapter describes various
techniques you can use to customize your installation.
NOTE:
The device operates in IRF or standalone (the default) mode. For information about IRF mode, see IRF
Configuration Guide.
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Enabling an interface to receive and forward
directed broadcasts destined for the directly
connected network
A directed broadcast packet is destined for all hosts on a specific network. In the destination IP address
of the directed broadcast, the network ID identifies the target network, and the host ID is made up of all
ones.
If an interface is allowed to forward directed broadcasts destined for the directly connected network,
hackers can exploit this vulnerability to attack the target network. In some scenarios, however, an
interface must receive and send such directed broadcast packets to support UDP helper and Wake on
LAN.
This task enables an interface to accept directed broadcast packets that are destined for and received
from the directly connected network to support UDP helper, which converts the directed broadcasts to
unicasts and forwards them to a specific server.
The task also enables the interface to forward directed broadcast packets that are destined for the
directly connected network and are received from another subnet to support Wake on LAN, which sends
the directed broadcasts to wake up the hosts on the target network.
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Configuration procedure
CAUTION:
The link and link protocol of an interface must be up before the interface forwards directed broadcasts.
To enable an interface to receive and forward directed broadcasts destined to the directly connected
network:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface view.
interface interface-type
interface-number
N/A