Thursday, June 28, 2018

Google DNS IPv6 Design

Edit: In my limited understanding of Anycast services I would assume longer prefixes than /48 could be inside of service provider networks where Google potentially has DNS servers setup.

Given the two Google IPv6 DNS addresses:

2001:4860:4860::8888

2001:4860:4860::8844

It seems odd to me that what should (?) be operationally distinct addresses are in the same /48 (ultimately the same /32,/48,/64, etc.) which is what I understand to be the longest prefix that is globally routable. Given that the two DNS addresses are in the same /64, both of their services will at least go partially down with one /48 prefix hijack correct?

redacted#sh ipv6 route vrf redacted 2001:4860:4860::8888

Routing entry for 2001:4860::/32

Known via "bgp redacted", distance 20, metric 0, type external

Route count is 1/1, share count 0

Routing paths:

FE80::214:F600:2B4:65F4, GigabitEthernet0/0/0

MPLS label: nolabel

Last updated 5d19h ago

redacted#sh ipv6 route vrf redacted 2001:4860:4860::8844

Routing entry for 2001:4860::/32

Known via "bgp redacted", distance 20, metric 0, type external

Route count is 1/1, share count 0

Routing paths:

FE80::214:F600:2B4:65F4, GigabitEthernet0/0/0

MPLS label: nolabel

Last updated 5d19h ago



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