The ipv6 icmp hop-limit-exceeded send command enables an interface to send ICMPv6 Hop Limit Exceeded messages.
The undo ipv6 icmp hop-limit-exceeded send command disables the function.
By default, the enabling status of the function that the interface sends ICMPv6 Hop Limit Exceeded messages is the same as that of the function that the system sends ICMPv6 Hop Limit Exceeded messages.
If a router receives a packet with a hop limit of 1, it replies with an ICMPv6 Hop Limit Exceeded message. This ICMPv6 error message carries the IPv6 address of the router as its source IPv6 address, which exposes the IPv6 address of the router and brings security risks. If the router is attacked by flooding packets, the router keeps replying with ICMPv6 Hop Limit Exceeded messages, causing high CPU usage and affecting device performance. To address this problem, run the undo ipv6 icmp hop-limit-exceeded send command on the inbound interface of ICMPv6 packets to disable the transmission of ICMPv6 Hop Limit Exceeded messages.
# Disable VLANIF100 from sending ICMPv6 Hop Limit Exceeded messages.
<HUAWEI> system-view [HUAWEI] interface vlanif 100 [HUAWEI-Vlanif100] ipv6 enable [HUAWEI-Vlanif100] undo ipv6 icmp hop-limit-exceeded send
# Disable interface GE0/0/1 from sending ICMPv6 Hop Limit Exceeded messages.
<HUAWEI> system-view [HUAWEI] ipv6 [HUAWEI] interface gigabitethernet 0/0/1 [HUAWEI-GigabitEthernet0/0/1] undo portswitch [HUAWEI-GigabitEthernet0/0/1] ipv6 enable [HUAWEI-GigabitEthernet0/0/1] undo ipv6 icmp hop-limit-exceeded send