subnet.im

AS51044Kazuki Yamaguchi

JapanRegistryRIPE NCC

As of 27th September 2026, AS51044 (Kazuki Yamaguchi), a network registered in Japan with RIPE NCC, originates 3 IPv4 prefixes covering 1.5k addresses and 18 IPv6 prefixes. By IPv4 address space that makes it the 31,108th-largest of the 79,525 networks we see originating IPv4, and the 500th-largest of 729 in Japan. It is seen behind 6 upstream networks, most often AS20473 (The Constant Company, LLC) and AS34549 (meerfarbig GmbH & Co. KG). Every one of its announcements has a valid RPKI ROA, and none are RPKI-invalid. 57% of its routes reach at least 90% of full-feed peers.

At a glance

IPv4 prefixes

3

IPv6 prefixes

18

IPv4 addresses

1.5k

IPv6 /64s

8.6B

Upstream graph

The networks AS51044 is seen behind, one and two hops out, drawn from real AS paths.

AS51044Toward the internet core
Upstream graph for AS51044: 12 neighbouring networks observed beyond it across 2 levels. The same networks are listed in the tables below.AS51044Kazuki YamaguchiThis networkAS6939Hurricane Electri…AS20473The Constant Comp…AS34549meerfarbig GmbH &…AS57578Misaka Network, I…AS57695Misaka Network, I…AS20130Depaul UniversityAS1299Arelion (fka. Tel…AS2914NTT America, Inc.AS56662Marcin GondekAS213151Christian ElsenAS9002RETN LimitedAS210756EdgeCenter LLC

Networks observed one and two hops upstream of AS51044 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

12

adjacent networks

Upstreams
650%
Peers
650%
Downstreams
00%

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

Upstreams of AS51044
NetworkCountryRelationshipPathsVantage pts
AS20473The Constant Company, LLCUSPeer36789
AS34549meerfarbig GmbH & Co. KGDEPeer23576
AS57578Misaka Network, Inc.USPeer20667
AS6939Hurricane Electric LLCUSPeer12563
AS57695Misaka Network, Inc.USPeer10134
AS142616Misaka Network, Inc.JPPeer155

Prefixes

The largest blocks AS51044 originates, widest first.

Largest prefixes originated by AS51044
PrefixAddressesVisibility
45.148.172.0/221k80/81
45.148.172.0/2425681/81
45.148.173.0/2425681/81
2a0f:601::/324.3B × /6464/64
2a0f:602::/324.3B × /6464/64
2a0f:600:604::/46262k × /6464/64
2a0f:600:604::/47131k × /6424/64
2a0f:600:608::/47131k × /6463/64
2a0f:600:60a::/47131k × /6463/64
2a0f:600:60c::/47131k × /6462/64

Routing health

How AS51044'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%21
  • Invalid0.0%0
  • No ROA0.0%0

Propagation

  • Globally propagated90% of full-feed peers or more57.1%12
  • Partially propagated40% to 90%19.0%4
  • Seen by few peersUnder 40%23.8%5

Prefix sizes

IPv4 — 3 prefixes

IPv6 — 18 prefixes

  • /324.3B × /6411.1%2
  • /46262k × /645.6%1
  • /47131k × /6422.2%4
  • /4865.5k × /6461.1%11

Recent changes

Announcements that started or stopped since 28th Aug 2026.

No announcement by AS51044 started or stopped in this period.

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