Operation Manual – IP Address and PerformanceH3C S5600 Series Ethernet Switches Chapter 2 IP Performance Configuration2-3z Using the UDP Helper function to convert broadcasts to unicasts and forwardthem to a specified server.z Using the Wake on LAN function to forward directed broadcasts to a host on theremote network.Follow these steps to enable the switch to receive and Forwarding directed broadcasts:To do… Use the command… RemarksEnter system view system-view —Enable the device toreceive directedbroadcastsip forward-broadcast RequiredDisabled by default.Enter VLAN interface view interface Vlan-interfacevlan-id —Enable the device toforward directedbroadcastsip forward-broadcast[ acl-number ]RequiredDisabled by default.2.2.4 Disabling ICMP to Send Error PacketsSending error packets is a major function of ICMP protocol. In case of networkabnormalities, ICMP packets are usually sent by the network or transport layerprotocols to notify corresponding devices so as to facilitate control and management.Although sending ICMP error packets facilitate control and management, it still has thefollowing disadvantages:z Sending a lot of ICMP packets will increase network traffic.z If receiving a lot of malicious packets that cause it to send ICMP error packets, thedevice’s performance will be reduced.z As the ICMP redirection function increases the routing table size of a host, thehost’s performance will be reduced if its routing table becomes very large.z If a host sends malicious ICMP destination unreachable packets, end users maybe affected.You can disable the device from sending such ICMP error packets for reducing networktraffic and preventing malicious attacks.Follow these steps to disable sending ICMP error packets:To do… Use the command… RemarksEnter system view system-view —Disable sending ICMPredirects undo icmp redirect send RequiredEnabled by default.
