Mailing List Archive

IPv6 in GCP (WTH?): default route
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@gont.com.ar
PGP Fingerprint: 7F7F 686D 8AC9 3319 EEAD C1C8 D1D5 4B94 E301 6F01