asn.dev

Autonomous system

AS23781 TOYAMA-AN-AS Toyama University

Unclassified ARIN

IPv4 addresses 72.70K 4 prefixes
IPv6 prefixes 0 counted as prefixes, not addresses
Countries 1 mostly JP
Exchanges 0 recorded by PCH
Upstreams 1 0 downstream
Flagged prefixes 0 none

Summary

Toyama University

Japan · AI-generated

education university japan

TOYAMA-AN-AS is operated by Toyama University.

What it's used for

  • The address space carries university network traffic, evidenced by reverse DNS entries pointing to TMPU-net.u-toyama.ac.jp and netnames such as TYA-NET and TYA-NET-CIDR-BLK-JP.
  • The AS announces 72,704 IPv4 addresses across 4 prefixes with only 1 observed neighbour, a ratio characteristic of an access or eyeball network serving a single institution rather than a transit provider.

Notable

  • Registrants for all announced prefixes are listed as Japan Network Information Center or IRT-JPNIC-JP, which aligns with the announcer being a Japanese academic institution.
  • The inventory consists of one large /16 block and three smaller blocks (/20, /21, /22), all located in Japan.

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

No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.

Transit providers

1 upstream, 0 downstream and 1 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS2907Research Organization of Information and Systems, National Institute of Informatics247

Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-26, 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 4 prefixes · 72.70K addresses IPv6 0 prefixes

CountryNamePrefixes
JPJapan4

Registry

Allocation record

ARIN · via Atlas (registry + RDAP)
Registry
ARIN
Handle
AS23781
Registry name
Toyama-AN-AS
Abuse contact
hostmaster@nic.ad.jp
Registered
2003-06-16
Last changed
2011-03-10
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
0% valid · 0 valid, 4 with no ROA
ROAs
0 authorising AS23781
ASPA
no ASPA record
IRR
0% registered · 0 of 4 announcements
Route objects
0 naming AS23781

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: 446 networks and 1,852 prefixes, as published 2026-10-27. 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