Reputation · trust score
A transparent 0–100 signal. Every entity starts at a neutral baseline of 65; threat-intel blocklists, exposure, reverse-DNS, routing and allocation each adjust it up or down. Higher is more trustworthy.
- Baseline (neutral) 65
- Academic allocation +6
- Trust score 71 / 100
Experimental · trust-vectors model v1.1.0 — a transparent heuristic, not a definitive verdict. How it works →
AS2501 — global IP footprint
Cities where AS2501 has measurable IPv4 allocation. Click any dot to open that city's page. Size and color scale with IP count.
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 130.69.0.0/16 | 65.5K |
2.5%
|
The University of Tokyo | JP | Tokyo | Yanaka |
| 133.11.0.0/16 | 65.5K |
15.3%
|
The University of Tokyo | JP | Tokyo | Koishikawa |
| 157.82.0.0/16 | 65.5K |
21.1%
|
The University of Tokyo | JP | Tokyo | Tokyo |
| 192.51.208.0/20 | 4.1K |
0.3%
|
The University of Tokyo | JP | Tokyo | Matsubara |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS2501 actually originates in BGP, observed across our RIPE RIS collectors. This live routing view can differ from the registry allocation above.
| Prefix | Announcement samples | Last seen |
|---|---|---|
| 130.69.0.0/16 | 4,486 | 2026-07-23 15:46:05 |
| 192.51.208.0/20 | 4,473 | 2026-07-23 15:46:05 |
| 133.11.0.0/16 | 4,419 | 2026-07-23 15:46:05 |
| 157.82.0.0/16 | 4,417 | 2026-07-23 15:45:07 |
Frequently Asked Questions
What is AS2501?
AS2501 is an Autonomous System Number assigned to The University of Tokyo. An ASN identifies a network that controls a specific set of IP addresses and determines how traffic is routed across the internet via BGP (Border Gateway Protocol).
How many IP addresses does AS2501 announce?
AS2501 announces 200.7K IPv4 addresses distributed across 4 routed CIDR prefixes. The network is registered in Japan.
Who operates AS2501?
AS2501 is operated by The University of Tokyo. The organization is based in Japan. You can view all IP ranges and related ASNs on the organization page.
What country is AS2501 registered in?
AS2501 is registered in Japan. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
