Hello misc,
Running 6.4-beta from approximately a week ago.
1) How to determine the IPv6 multicast groups which have been joined by
a particular interface?
I have tried netstat but have been unsuccessful.
# ifconfig em0
em0:
flags=648843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST,INET6_NOPRIVACY,AUTOCONF6,INET6_NOSOII>
mtu 1500
...
status: active
...
inet6 <link_local_unicast_address>%em0 prefixlen 64 scopeid 0x1
inet6 <global_unicast_address> prefixlen 64 autoconf pltime xxxxxx
vltime xxxxxxx
# cat /etc/pf.conf
...
pass quick on egress inet6 proto icmp6
...
# netstat -g
Virtual Interface Table is empty
Multicast Forwarding Cache is empty
IPv6 Multicast Interface Table is empty
IPv6 Multicast Routing Table is empty
2) How to disable an interface from joining IPv6 Node Information
multicast group (RFC 4620)?
In sys/netinet6/in6.c, the function in6_update_ifa contains the
following lines:
/*
* join node information group address
*/
if (in6_nigroup(ifp, hostname, hostnamelen, &mltaddr) == 0) {
imm = in6_joingroup(ifp, &mltaddr.sin6_addr, &error);
if (!imm) {
/* XXX not very fatal, go on... */
} else {
LIST_INSERT_HEAD(&ia6->ia6_memberships,
imm, i6mm_chain);
}
}
Since I cannot determine the multicast groups that an interface joins,
I cannot ascertain whether the Node Information multicast group is
joined by the egress interface or not.
Some noteworthy excerpts/sections from RFC 4620:
Status of This Memo
This memo defines an Experimental Protocol for the Internet
community.
1. Introduction
This document specifies a mechanism for discovering information about
names and addresses. The applicability of these mechanisms is
currently limited to diagnostic and debugging tools and network
management (e.g., node discovery).
8. Security Considerations
https://tools.ietf.org/html/rfc4620#section-8
I understand that IPv6 is a challenging subject for me. In my layman
understanding, I am trying to disable RFC 4620 because it is an
experimental protocol with no evident use, for me atleast.
Thanks.
Regards,
ab
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