Re: IPv6 with DHCP -- how is default route set?

[Eloy Paris <peloy chapus net>]

Hi Dan,

On Wed, Oct 21, 2015 at 10:40:00AM -0500, Dan Williams wrote:

> On Tue, 2015-10-20 at 22:38 +0300, Andrei Borzenkov wrote:
> > 20.10.2015 21:23, Eloy Paris пишет:
> > > Do we not send router solicitation messages to avoid having to wait for
> > > the next router advertisement message, which could happen who knows
> > > when?
> >
> > Yes. I do not know if NM does it.
>
> NM sends an RS at various points during the connection activation
> process.  There used to be some issues with that (like, 0.9.10) but
> we've fixed those for 1.0.x series.  If you wireshark you should see
> them.

Here's what I see when I bring up an Ethernet interface on my corporate
network:

shell$ tcpdump -n -r /tmp/ra.pcap icmp6  or port 67
reading from file /tmp/ra.pcap, link-type EN10MB (Ethernet)
10:42:44.162807 IP 10.150.226.114.68 > 255.255.255.255.67: BOOTP/DHCP, Request from xx:xx:xx:0c:20:b6, length 
300
10:42:44.165982 IP 10.150.226.1.67 > 255.255.255.255.68: BOOTP/DHCP, Reply, length 300
10:42:45.079969 IP 0.0.0.0.68 > 255.255.255.255.67: BOOTP/DHCP, Request from xx:xx:xx:79:a5:b7, length 300
10:42:45.096235 IP 10.150.226.1.67 > 10.150.226.110.68: BOOTP/DHCP, Reply, length 308
10:42:45.327745 IP6 :: > ff02::1:ff79:a5b7: ICMP6, neighbor solicitation, who has fe80::xxxx:xxxx:fe79:a5b7, 
length 24
10:42:46.328199 IP6 fe80::xxxx:xxxx:fe79:a5b7 > ff02::2: ICMP6, router solicitation, length 8
10:42:50.312164 IP6 fe80::xxxx:xxxx:fe79:a5b7 > ff02::2: ICMP6, router solicitation, length 8
10:42:54.312363 IP6 fe80::xxxx:xxxx:fe79:a5b7 > ff02::2: ICMP6, router solicitation, length 8
10:43:10.767278 IP6 fe80::xxxx:xxxx:feff:fd90 > ff02::1: ICMP6, router advertisement, length 64

So yes, NM is sending router solicitation messages. It is my next-hop
router the one that it is not responding for some reason. I'll take this
up with the corporate IT folks after doing some additional research on
my own.

Cheers,

Eloy Paris.-