On Mon, Mar 15, 2021 at 05:29:55PM -0700, Doug Hardie wrote: > I reduced the configuration to the host settings: > ifconfig_bge0_ipv6="inet6 accept_rtadv" > > The router to: > ifconfig_ue0_ipv6="up" > > Ran tcpdump on the router (obviously not acting as a router) and restarted > the host. Got the following: > > tcpdump: listening on ue0, link-type EN10MB (Ethernet), capture size 262144 > bytes
The device is using a EUI-64 link local address, which is unique by definition. Therefore no DAD is necessary, the address can be used immediatly. If you use a manually generated address, even if it has a EUI-64 form, DAD is required. DAD consists of Neighbour Solication messages. I understand your point, questioning if DAD should be done in any case or not. That's a complicated topic, which requires a lot of RFC exegesis, studying interop tests results from the IETF and IPv6 certificate organisations, and practical market dominance. > 19:05:00.048637 IP6 (hlim 1, next-header Options (0) payload length: 56) > fe80::aa60:b6ff:fe1d:8dbc > ff02::16: HBH (padn)(rtalert: 0x0000) [icmp6 sum > ok] ICMP6, multicast listener report v2, 2 group record(s) [gaddr > ff02::2:ec7d:574c to_ex, 0 source(s)] [gaddr ff02::2:ffec:7d57 to_ex, 0 > source(s)] Because IPv6 uses unicast and multicast only, the device registers itself for the necessary link local multicast groups. > 19:05:00.171029 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 16) > fe80::aa60:b6ff:fe1d:8dbc > ff02::2: [icmp6 sum ok] ICMP6, router > solicitation, length 16 > source link-address option (1), length 8 (1): a8:60:b6:1d:8d:bc The device will use SLAAC for address configuration, but do not want to wait for the next Router Advertisement, so it asks for an immediate response from the router. > 19:05:04.198640 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 16) > fe80::aa60:b6ff:fe1d:8dbc > ff02::2: [icmp6 sum ok] ICMP6, router > solicitation, length 16 > source link-address option (1), length 8 (1): a8:60:b6:1d:8d:bc No router answered, maybe the packet was lost. So the device ask again for a router in order to complete SLAAC. > 19:05:08.449844 IP6 (hlim 255, next-header ICMPv6 (58) payload length: 16) > fe80::aa60:b6ff:fe1d:8dbc > ff02::2: [icmp6 sum ok] ICMP6, router > solicitation, length 16 > source link-address option (1), length 8 (1): a8:60:b6:1d:8d:bc No router answered, maybe the packet was lost. So the device ask again for a router in order to complete SLAAC. _______________________________________________ freebsd-net@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
