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
- Trust score 65 / 100
Experimental · trust-vectors model v1.2.0 — a transparent heuristic, not a definitive verdict. How it works →
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 76.9.158.0/23 | 512 |
0.0%
|
Fairfax County NCR | US | — | — |
| 76.9.155.0/24 | 256 |
0.0%
|
Fairfax County NCR | US | — | — |
| 76.9.156.0/24 | 256 |
0.0%
|
Fairfax County NCR | US | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS401999 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 |
|---|---|---|
| 76.9.155.0/24 | 6,441 | 2026-08-05 00:27:48 |
| 76.9.156.0/24 | 6,439 | 2026-08-05 00:27:48 |
| 76.9.159.0/24 | 5,405 | 2026-08-04 23:53:06 |
| 76.9.158.0/24 | 5,388 | 2026-08-04 23:53:06 |
Frequently Asked Questions
What is AS401999?
AS401999 is an Autonomous System Number assigned to Fairfax County NCR. 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 AS401999 announce?
AS401999 announces 1.0K IPv4 addresses distributed across 3 routed CIDR prefixes. The network is registered in United States.
Who operates AS401999?
AS401999 is operated by Fairfax County NCR. The organization is based in United States. You can view all IP ranges and related ASNs on the organization page.
What country is AS401999 registered in?
AS401999 is registered in United States. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
