IPv6 in GCP (WTH?): default route

[Fernando Gont]

Hi. all,

I happen to be playing with IPv6 on GCP, and seem to find a few 
"interesting" things.

RAs on the IPv6 subnet are as follows:

---- cut here ----
rdisc6 ens5
Soliciting ff02::2 (ff02::2) on ens5...

Hop limit                 :    undefined (      0x00)
Stateful address conf.    :          Yes
Stateful other conf.      :           No
Mobile home agent         :           No
Router preference         :       medium
Neighbor discovery proxy  :           No
Router lifetime           :            0 (0x00000000) seconds
Reachable time            :  unspecified (0x00000000)
Retransmit time           :  unspecified (0x00000000)
  Source link-layer address: 42:01:0A:0B:00:01
  MTU                      :         1460 bytes (valid)
  Route                    : 2600:1900:4121:3b52::/65
   Route preference        :       medium
   Route lifetime          :           90 (0x0000005a) seconds
  from fe80::4001:aff:fe0b:1
---- cut here ----

As you can tell from the RA, it has a Router Lifetime of 0, so a 
compliant implementation will not install an IPv6 default router.

(yes, the router sending this RA will work okay as a default router if 
you manually configure it as such, though).

GCP claims that you can get the default route for an interface by 
querying the local metadata server 
(https://cloud.google.com/compute/docs/ip-addresses/configure-ipv6-address)... 
which I guess one would query over IPv4? :-)

Thoughts? Comments? Input?

Thanks!

Regards,
-- 
Fernando Gont
e-mail: fernando at gont.com.ar
PGP Fingerprint: 7F7F 686D 8AC9 3319 EEAD C1C8 D1D5 4B94 E301 6F01