ipv6 icmp hop-limit-exceeded send

Function

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 transmission of ICMPv6 Hop Limit Exceeded messages configured globally also takes effect on an interface.

Format

ipv6 icmp hop-limit-exceeded send

undo ipv6 icmp hop-limit-exceeded send

Parameters

None

Views

Ethernet interface view, Eth-Trunk interface view, Tunnel interface view, VLANIF interface view, BDIF interface view

Default Level

2: Configuration level

Usage Guidelines

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 outbound interface of ICMPv6 packets to disable the transmission of ICMPv6 Hop Limit Exceeded messages.

Example

# Disable GE0/0/1 from sending ICMPv6 Hop Limit Exceeded messages.

<sysname> system-view

[sysname] interface GigabitEthernet 0/0/1

[sysname-GigabitEthernet0/0/1] undo ipv6 icmp hop-limit-exceeded send