1-18are received, the finwait timer is reset upon receipt of the last non-FIN packet and the connection isterminated after the finwait timer expires.z Size of the IPv6 TCP sending/receiving buffer.Follow these steps to configure IPv6 TCP properties:To do… Use the command… RemarksEnter system view system-view —Set the finwait timer tcp ipv6 timer fin-timeoutwait-timeOptional675 seconds by default.Set the synwait timer tcp ipv6 timer syn-timeoutwait-timeOptional75 seconds by default.Set the size of the IPv6 TCPsending/receiving buffer tcp ipv6 window size Optional8 KB by default.Configuring ICMPv6 Packet SendingConfiguring the Maximum ICMPv6 Error Packets Sent in an IntervalIf too many ICMPv6 error packets are sent within a short time in a network, network congestion mayoccur. To avoid network congestion, you can control the maximum number of ICMPv6 error packetssent within a specified time, currently by adopting the token bucket algorithm.You can set the capacity of a token bucket, namely, the number of tokens in the bucket. In addition, youcan set the update interval of the token bucket, namely, the interval for restoring the configured capacity.One token allows one ICMPv6 error packet to be sent. Each time an ICMPv6 error packet is sent, thenumber of tokens in a token bucket decreases by one. If the number of ICMPv6 error packetssuccessively sent exceeds the capacity of the token bucket, the additional ICMPv6 error packets cannotbe sent out until the capacity of the token bucket is restored.Follow these steps to configure the capacity and update interval of the token bucket:To do… Use the command… RemarksEnter system view system-view —Configure thecapacity and updateinterval of the tokenbucketIpv6 icmp-error { bucketbucket-size | ratelimitinterval } *OptionalBy default, the capacity of a token bucket is 10and the update interval is 100 milliseconds.That is, at most 10 IPv6 ICMP error packetscan be sent within 100 milliseconds.The update interval “0” indicates that thenumber of ICMPv6 error packets sent is notrestricted.Enabling Replying to Multicast Echo RequestsIf hosts are configured to answer multicast echo requests, an attacker may use this mechanism toattack a host. For example, if Host A sends an echo request with the source being Host B to a multicastaddress, then all the hosts in the multicast group will send echo replies to Host B. Therefore, to preventsuch an attack, a device is disabled from replying multicast echo requests by default.
