Tiens, je remets une couche sur ce sujet - on ne pourra pas me dire qu’il ne m’intéresse pas - 
En effet, pour certaines raisons récentes, je me suis replonger dans certaines documentations glanées sur le web, et principalement auprès de l’IETF … dont la fameuse RFC 4890, et ces recommandations de filtrage ICMPv6 en local, ainsi que de ce document de travail de 2013-2014 !
Selon lesdites recommandations, il semble intéressant d’écrire ainsi les règles ICMPv6 :
ip6tables -N INPUT_ICMPV6
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 1 -m limit --limit 1/second -j ACCEPT # destination-unreachable; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 2/0 -j ACCEPT # packet too big; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 3/0 -j ACCEPT # time exceeded; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 3/1 -j ACCEPT # time exceeded; Should Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 4/0 -m limit --limit 1/second -j ACCEPT # parameter pb: Erroneous header field encountered; Should Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 4/1 -m limit --limit 1/second -j ACCEPT # parameter pb: Unrecognized Next Header Type encountered; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 4/2 -m limit --limit 1/second -j ACCEPT # parameter pb: Unrecognized IPv6 option encountered; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 128/0 -m limit --limit 1/second -j ACCEPT # ping tool: echo request message; Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 129/0 -m limit --limit 1/second -j ACCEPT # ping tool: echo reply message; Must Not Be Dropped
# link-local multicast receive notification mssg (need link-local src address)
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 130/0 -s fe80::/64 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 131/0 -s fe80::/64 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 132/0 -s fe80::/64 -j ACCEPT # Must Not Be Dropped
# address configuration and routeur selection mssg (received with hop limit = 255)
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 133/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -s fe80::/64 -p icmpv6 --icmpv6-type 134/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 135/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 136/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 141/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 142/0 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
# link-local multicast receive notification mssg (need link-local src address)
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 143 -s fe80::/64 -j ACCEPT # Must Not Be Dropped
# SEND certificate path notification mssg (received with hop limit = 255)
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 148 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 149 -m state --state RELATED -m hl --hl-eq 255 -j ACCEPT # Must Not Be Dropped
# multicast routeur discovery mssg (need link-local src address and hop limit = 1)
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 151 -s fe80::/64 -m hl --hl-eq 1 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 152 -s fe80::/64 -m hl --hl-eq 1 -j ACCEPT # Must Not Be Dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 --icmpv6-type 153 -s fe80::/64 -m hl --hl-eq 1 -j ACCEPT # Must Not Be Dropped
# all others are dropped
ip6tables -A INPUT_ICMPV6 -p icmpv6 -j DROPBien-sûr, l’équivalent en sortie est à traiter …
Voilà, où j’en suis de mes recherches et compréhensions actuelles, selon lesdites documentations.