SLAAC not working

[Andrey V. Elsukov]

On 05.09.2017 00:20, Greg Rivers wrote:
> Thanks. Trying your same experiment, I do get output for duplicate detection, though it doesn't include the interface identifier or a check for the auto generated link-local address (maybe you're running -CURRENT?):

Yes, it is CURRENT, but auto generated address is there because lagg0
did not have enabled IPv6 at beginning of test.

> # ifconfig lagg0 inet6 fe80::8/64
> # ifconfig lagg0 inet6 fe80::8/64 delete
> # dmesg | tail -2
> lagg0: starting DAD for fe80:c::8
> lagg0: DAD complete for fe80:c::8 - no duplicates found
> 
> What puzzles me is that there are two Cisco routers on this network that each send RAs every ~10 minutes, yet nothing is ever logged on the host, and the RAs, which should trigger address auto-configuration, are completely ignored.

You can try to use dtrace to detect that RA is received by IPv6 stack.
# kldload dtraceall
#  dtrace -n 'fbt::nd6_ra_input:entry {m = (struct mbuf *)arg0; ip6 =
(struct ip6_hdr *)m->m_data; printf("RA from %s received on %s",
inet_ntoa6(&ip6->ip6_src), stringof(m->m_pkthdr.rcvif->if_xname));}'

It should produce the output like this:
dtrace: description 'fbt::nd6_ra_input:entry ' matched 1 probe
CPU     ID                    FUNCTION:NAME
  2  37912               nd6_ra_input:entry RA from
fe80:1::92e2:baff:fe6a:c7c received on ix0
  2  37912               nd6_ra_input:entry RA from
fe80:1::92e2:baff:fe6a:c7c received on ix0

> $ ping6 fe80:XXXX:XXXX:4013:23::2%lagg0
> ping6: UDP connect: Network is unreachable

Hmm. Can you show the second word of address in this example?
Is it not zero? I.e. fe80:XXXX: is correct or you missed '::' part?

-- 
WBR, Andrey V. Elsukov

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