asn.dev

Autonomous system

AS12276 SFMIX-MGMT

Unclassified ARIN

IPv4 addresses 256 1 prefixes
IPv6 prefixes 4 counted as prefixes, not addresses
Countries 1 mostly US
Exchanges 1 recorded by PCH
Upstreams 3 0 downstream
Flagged prefixes 0 none

Summary

SFMIX

United States · AI-generated

ixp legacy

The management network of the San Francisco Metropolitan Internet Exchange.

What it's used for

  • Exchange infrastructure and management. 256 addresses in one /24, four IPv6 announcements, six observed BGP neighbours.

Notable

  • The IPv4 block is named for its job: 192.33.255.0/24, netname SFMIX-V4-MANAGEMENT.
  • The four IPv6 announcements form a chain out of 2620:11a:b000:: — a /47, then a /48, a /46 and a /45, together covering everything from b000 to b00f apart from 2620:11a:b002::/48.
  • Six neighbours. An exchange operator's own network needs to be reachable from the outside, which is a different requirement from the fabric it operates.

Interesting

  • The missing /48 in the middle of that chain is the kind of hole an exchange point produces. Peering LAN prefixes are conventionally kept out of the global routing table, so that the fabric is reachable only from the fabric, and the operator announces everything around it.
  • What an IXP actually is, in routing terms, is almost nothing: a switch, a room, and an agreement. The addresses here run the portal, the route servers' management side and the monitoring. The traffic that makes the exchange worth existing never appears in this AS at all.

This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.

Interconnection

Peering at a glance

Full topology · Graph

Internet exchanges

Recorded at 1 exchange in 1 country, largest first.

ExchangeLocationTheir address
San Francisco Metropolitan Internet ExchangeSan Francisco, United States206.197.187.1

Transit providers

3 upstream, 0 downstream and 6 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS6939Hurricane Electric LLC121
AS1299Arelion Sweden AB12
AS36086Telx5

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-11, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.

Address space

Summary

Shape and geography

IPv4 1 prefixes · 256 addresses IPv6 4 prefixes

CountryNamePrefixes
USUnited States of America5

Registry

Allocation record

ARIN · via Atlas (registry + RDAP)
Registry
ARIN
Handle
AS12276
Registry name
SFMIX-MGMT
Registrant
San Francisco Metropolitan Internet Exchange (SFMIX)
Abuse contact
tech-c@sfmix.org
Registered
2007-06-04
Last changed
2014-06-12
Allocation
assigned

Routing security

RPKI and IRR

Full detail
RPKI
100% valid · 3 valid, 0 with no ROA
ROAs
2 authorising AS12276
ASPA
3 declared providers
IRR
100% registered · 3 of 3 announcements
Route objects
6 naming AS12276

Reputation

Classification and threat

Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.

Spamhaus DROP

Not on ASN-DROP The network as a whole is not listed.

No DROP prefixes None of its announced space is on the DROP prefix list.

Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 431 networks and 1,768 prefixes, as published 2026-10-12. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.

FBI IC3

No IC3 indicators Nothing from the FBI IC3 feed.

IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.

Elsewhere

Cross-check