1-7Disadvantages of sending ICMP error packetsAlthough sending ICMP error packets facilitates network control and management, it still has thefollowing disadvantages:z Sending a lot of ICMP packets will increase network traffic.z If a device receives a lot of malicious packets that cause it to send ICMP error packets, itsperformance will be reduced.z As the redirection function increases the routing table size of a host, the host’s performance will bereduced if its routing table becomes very large.z If a host sends malicious ICMP destination unreachable packets, end users may be affected.To prevent such problems, you can disable the device from sending ICMP error packets.Follow these steps to enable sending of ICMP error packets:To do… Use the command… RemarksEnter system view system-view —Enable sending of ICMP redirect packets ip redirects enable RequiredDisabled by default.Enable sending of ICMP timeout packets ip ttl-expires enable RequiredDisabled by default.Enable sending of ICMP destinationunreachable packets ip unreachables enable RequiredDisabled by default.The device stops sending “TTL timeout” ICMP error packets after sending ICMP timeout packets isdisabled. However, “reassembly timeout” error packets will be sent normally.Displaying and Maintaining IP Performance OptimizationTo do… Use the command… RemarksDisplay current TCP connectionstate display tcp status Available in any viewDisplay TCP connection statistics display tcp statistics Available in any viewDisplay UDP statistics display udp statistics Available in any viewDisplay statistics of IP packets display ip statistics Available in any viewDisplay ICMP statistics display icmp statistics Available in any viewDisplay socket information display ip socket [ socktypesock-type ] [ task-id socket-id ] Available in any viewDisplay FIB informationdisplay fib [ | { begin | include |exclude } regular-expression | aclacl-number | ip-prefixip-prefix-name ]Available in any view
