Like its counterpart for IPv4, Internet Control Message Protocol version 6 (ICMPv6) plays an essential role for the functioning of IPv6. But, as this informational RFC would show, there are a number of security risks associated with uncontrolled forwarding of ICMPv6 messages.

This RFC provides some recommendations for ICMPv6 firewall filter configuration that will allow propagation of ICMPv6 messages needed to maintain the functioning of the network, but drop messages that are potential security risks. Read RFC4890