AS31
California Institute of Technology
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 v1.2.0 — a transparent heuristic, not a definitive verdict. How it works →
About California Institute of Technology
The California Institute of Technology (branded as Caltech) is a private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of institutes of technology in the United States that are devoted to the instruction of pure and applied sciences.
AS31 — global IP footprint
Cities where AS31 has measurable IPv4 allocation. Click any dot to open that city's page. Size and color scale with IP count.
Top CIDR ranges
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS31 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 |
|---|---|---|
| 134.4.0.0/16 | 19,720 | 2026-09-09 16:30:36 |
| 131.215.0.0/16 | 19,691 | 2026-09-09 16:30:36 |
| 192.41.208.0/24 | 18,173 | 2026-09-09 16:30:36 |
| 192.31.43.0/24 | 18,062 | 2026-09-09 16:30:36 |
| 192.12.19.0/24 | 17,840 | 2026-09-09 16:30:36 |
| 131.215.244.0/23 | 14,611 | 2026-09-09 19:55:15 |
| 131.215.240.0/24 | 13,752 | 2026-09-09 19:55:15 |
| 131.215.242.0/23 | 13,395 | 2026-09-09 19:55:15 |
| 131.215.234.0/24 | 13,256 | 2026-09-09 19:55:15 |
| 131.215.229.0/24 | 13,158 | 2026-09-09 19:55:15 |
| 131.215.230.0/24 | 13,081 | 2026-09-09 19:55:15 |
| 131.215.239.0/24 | 13,009 | 2026-09-09 19:55:15 |
Frequently Asked Questions
What is AS31?
AS31 is an Autonomous System Number assigned to California Institute of Technology. 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 AS31 announce?
AS31 announces 131.8K IPv4 addresses distributed across 20 routed CIDR prefixes. The network is registered in United States.
Who operates AS31?
AS31 is operated by California Institute of Technology. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.
What country is AS31 registered in?
AS31 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
