Re: IPv6 default route flapping

[Jan Schaumann <jschauma%netmeister.org@localhost>]

Greg Troxel <gdt%lexort.com@localhost> wrote:
> 
> Jan Schaumann <jschauma%netmeister.org@localhost> writes:
> 
> > Apr 20 01:32:32 netbsd dhcpcd[17397]: xennet0: soliciting an IPv6 router
> > Apr 20 01:32:34 netbsd dhcpcd[17397]: xennet0: Router Advertisement from fe80::caa:49ff:feaf:1815
> > Apr 20 01:32:35 netbsd dhcpcd[17397]: xennet0: fe80::caa:49ff:feaf:1815 is unreachable
> > Apr 20 01:32:35 netbsd dhcpcd[17397]: xennet0: soliciting an IPv6 router
> > Apr 20 01:32:44 netbsd dhcpcd[17397]: xennet0: fe80::caa:49ff:feaf:1815 is reachable again
> > Apr 20 01:32:52 netbsd dhcpcd[17397]: xennet0: fe80::caa:49ff:feaf:1815 is unreachable
> > Apr 20 01:32:52 netbsd dhcpcd[17397]: xennet0: soliciting an IPv6 router
> > Apr 20 01:32:54 netbsd dhcpcd[17397]: xennet0: Router Advertisement from fe80::caa:49ff:feaf:1815
> > Apr 20 01:32:55 netbsd dhcpcd[17397]: xennet0: fe80::caa:49ff:feaf:1815 is unreachable
> > Apr 20 01:32:56 netbsd dhcpcd[17397]: xennet0: soliciting an IPv6 router
> 
> I don't know what's wrong, but obviously you should 'tcpdump -w IPV6
> ip6' and look at it.

That's unfortunately not very revealing, as it merely
shows the neighbor solicitations and router advertisements:

IP6 fe80::7e12:b688:167c:785f > fe80::caa:49ff:feaf:1815: ICMP6, neighbor
solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > ff02::1:ffaf:1815:
ICMP6, neighbor solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > ff02::2: ICMP6, router solicitation, length 16
IP6 fe80::7e12:b688:167c:785f > ff02::1:ffaf:1815:
ICMP6, neighbor solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > ff02::1:ffaf:1815:
ICMP6, neighbor solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::caa:49ff:feaf:1815 > ff02::1: ICMP6, router advertisement, length 56
IP6 fe80::7e12:b688:167c:785f > ff02::1:ffaf:1815:
ICMP6, neighbor solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > ff02::2: ICMP6, router solicitation, length 16
IP6 fe80::7e12:b688:167c:785f > ff02::1:ffaf:1815:
ICMP6, neighbor solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > ff02::2: ICMP6, router solicitation, length 16
IP6 fe80::7e12:b688:167c:785f > ff02::2: ICMP6, router solicitation, length 16
IP6 fe80::caa:49ff:feaf:1815 > ff02::1: ICMP6, router advertisement, length 56
IP6 fe80::7e12:b688:167c:785f > fe80::caa:49ff:feaf:1815: ICMP6, neighbor
solicitation, who has fe80::caa:49ff:feaf:1815, length 32
IP6 fe80::7e12:b688:167c:785f > fe80::caa:49ff:feaf:1815: ICMP6, neighbor
solicitation, who has fe80::caa:49ff:feaf:1815, length 32

-Jan