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AS12276San Francisco Metropolitan Internet Exchange (SFMIX)

United StatesRegistryARIN

As of 23rd October 2026, AS12276 (San Francisco Metropolitan Internet…), a network registered in the United States with ARIN, originates 1 IPv4 prefix covering 256 addresses and 2 IPv6 prefixes. By IPv4 address space that makes it the 59,184th-largest of the 79,659 networks we see originating IPv4, and the 12,889th-largest of 18,482 in the United States. It is seen behind 4 upstream networks, most often AS6939 (Hurricane Electric LLC) and AS1299 (Arelion (fka. Telia Carrier)). Every one of its announcements has a valid RPKI ROA, and none are RPKI-invalid. 100% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

1

IPv6 prefixes

2

IPv4 addresses

256

IPv6 /64s

1.1M

Upstream graph

The networks AS12276 is seen behind, one and two hops out, drawn from real AS paths.

AS12276Toward the internet core
Upstream graph for AS12276: 10 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS12276San Francisco Met…This networkAS1299Arelion (fka. Tel…AS6939Hurricane Electri…AS36086Digital Realty (f…AS49544i3D.net B.VAS13030Init7 (Switzerlan…AS16552Tiggee LLCAS18106Viewqwest Pte LtdAS20130Depaul UniversityAS3356Lumen (Level 3)AS2914NTT America, Inc.

Networks observed one and two hops upstream of AS12276 in real AS paths. A thicker line means more vantage points saw that adjacency, so weight tracks how well attested it is — not how much traffic it carries. Adjacency is an observation; whether it is a transit purchase or a settlement-free peering is an inference, and is labelled as one wherever we show it.

Neighbouring networks

15

adjacent networks

Upstreams
427%
Peers
1173%
Downstreams
00%

Networks carrying this one's traffic toward the rest of the internet.

Upstreams of AS12276
NetworkCountryRelationshipPathsVantage pts
AS6939Hurricane Electric LLCUSPeer157107
AS1299Arelion (fka. Telia Carrier)SEPeer2821
AS36086Digital Realty (fka. Telx)USPeer1510
AS49544i3D.net B.VNLPeer32

Prefixes

The largest blocks AS12276 originates, widest first.

Largest prefixes originated by AS12276
PrefixAddressesVisibility
192.33.255.0/2425677/77
2620:11a:b000::/441M × /6463/64
2620:11a:b000::/4865.5k × /6463/64

Routing health

How AS12276's own announcements validate against RPKI and how far they propagate. The same measures for the whole routing table are on the routing table in numbers.

RPKI origin validation

  • Valid100.0%3
  • Invalid0.0%0
  • No ROA0.0%0

Propagation

  • Globally propagated90% of full-feed peers or more100.0%3
  • Partially propagated40% to 90%0.0%0
  • Seen by few peersUnder 40%0.0%0

Prefix sizes

IPv4 — 1 prefixes

IPv6 — 2 prefixes

  • /441M × /6450.0%1
  • /4865.5k × /6450.0%1

Recent changes

Announcements that started or stopped since 23rd Sept 2026.

No announcement by AS12276 started or stopped in this period.

Routing data derived from RouteViews MRT archives, BGPKIT relationship inference and public registry data.