R21xx-HP FlexFabric 11900 Layer 3 IP Services Command Reference

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Use undo ip forward-broadcast to disable an interface from receiving and forwarding directed
broadcast packets destined for the directly connected network.
Syntax
ip forward-broadcast
undo ip forward-broadcast
Default
An interface cannot receive or forward directed broadcasts destined for the directly connected network.
Views
Interface view
Predefined user roles
network-admin
Usage guidelines
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.
This command 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.
Examples
# Enable VLAN-interface 2 to receive and forward directed broadcast packets destined for the directly
connected network.
<Sysname> system-view
[Sysname] interface vlan-interface 2
[Sysname-Vlan-interface2] ip forward-broadcast
ip icmp fragment discarding
Use ip icmp fragment discarding to disable forwarding of ICMP fragments.
Use undo ip icmp fragment discarding to enable forwarding of ICMP fragments.
Syntax
ip icmp fragment discarding
undo ip icmp fragment discarding
Default
Forwarding of ICMP fragments is enabled.