The ipv6 icmp send command enables the system to send ICMPv6 messages.
The undo ipv6 icmp send command disables the system from sending ICMPv6 messages.
By default, the system is enabled to send ICMPv6 messages.
ipv6 icmp { icmpv6-type icmpv6-code | icmpv6-name | all } send
undo ipv6 icmp { icmpv6-type icmpv6-code | icmpv6-name | all } send
| Parameter | Description | Value |
|---|---|---|
| icmpv6-type | Specifies the type of an ICMPv6 message. | - |
| icmpv6-code | Specifies the code of an ICMPv6 message. | - |
| icmpv6-name | Specifies the name of an ICMPv6 message. | - |
| all | Indicates all ICMPv6 messages. | - |
| echo | Indicates an Echo message. | - |
| echo-reply | Indicates an Echo Reply message. | - |
| err-header-field | Indicates an ICMPv6 error header field message. | - |
| frag-time-exceeded | Indicates an ICMPv6 Fragment Time Exceeded message. | - |
| hop-limit-exceeded | Indicates an ICMPv6 Hop Limit Exceeded message. | - |
| host-admin-prohib | Indicates an ICMPv6 host administratively prohibited message. | - |
| host-unreachable | Indicates an ICMPv6 Host Unreachable message. | - |
| neighbor-advertisement | Indicates an ICMPv6 neighbor advertisement message. | - |
| neighbor-solicitation | Indicates an ICMPv6 neighbor solicitation message. | - |
| network-unreachable | Indicates an ICMPv6 Network Unreachable message. | - |
| packet-too-big | Indicates an ICMPv6 Packet Too Big message. | - |
| port-unreachable | Indicates an ICMPv6 Port Unreachable message. | - |
| redirect | Indicates an ICMPv6 redirect message. | - |
| router-advertisement | Indicates an ICMPv6 router advertisement message. | - |
| router-solicitation | Indicates an ICMPv6 router solicitation message. | - |
| unknown-ipv6-opt | Indicates an ICMPv6 unknown IPv6 option message. | - |
| unknown-next-hdr | Indicates an ICMPv6 unknown Next Header type message. | - |
Usage Scenario
In most cases, routers send a proper volume of ICMPv6 messages. If traffic is heavy on the network and hosts or ports are frequently unreachable, routers send a large number of ICMPv6 messages, which increases traffic burdens over the network and degrades the performance of routers. In addition, attackers usually use ICMPv6 error messages to probe the internal network topology.
To improve network performance and security, run the undo ipv6 icmp send command to disable the system from sending ICMPv6 Echo Reply messages, Host Unreachable messages, and Port Unreachable messages.
Precautions
When the network becomes normal again, you can run the ipv6 icmp send command to re-enable the system to send ICMPv6 messages.