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
- Active-threat / abuse risk −12
- Enterprise allocation +4
- Trust score 57 / 100
Experimental · trust-vectors model v1.3.0 — a transparent heuristic, not a definitive verdict. How it works →
About SURFnet
SURF is an organization that develops, implements and maintains the national research and education network (NREN) of the Netherlands. It operates the national research network formally called SURFnet.
⚠ 1 MOAS prefix — multiple origin ASNs detected
All MOAS anomalies →A previously stable prefix originated by AS1101 is now also announced by another ASN (MOAS — Multiple-Origin AS), detected from our RIPE RIS collectors. Often benign (anycast, multi-homing, or a recent transfer) — but it can signal a route leak or prefix hijack, so it's worth inspecting.
| Prefix | Origin ASNs | Last detected (UTC) |
|---|---|---|
| 185.17.73.0/24 | AS1101, AS61161 | 2026-11-08 21:08:27 |
Network profile
Source: PeeringDB →Present at 4 internet exchanges: AMS-IX, Frys-IX, Speed-IX: SPEED-IX, NL-ix: Main
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 145.192.0.0/12 | 1.05M |
99.6%
|
SURF B.V. | NL | — | — |
| 145.208.0.0/13 | 524.3K |
99.7%
|
SURF B.V. | NL | — | — |
| 145.216.0.0/15 | 131.1K |
99.9%
|
SURF B.V. | NL | — | — |
| 44.137.0.0/16 | 65.5K |
6.6%
|
SURF B.V. | US | — | — |
| 145.99.0.0/16 | 65.5K |
0.0%
|
SURF B.V. | NL | — | — |
| 145.220.0.0/16 | 65.5K |
90.4%
|
SURF B.V. | NL | — | — |
| 192.42.128.0/22 | 1.0K |
2.5%
|
SURF B.V. | NL | — | — |
| 145.102.4.0/23 | 512 |
0.0%
|
SURF B.V. | NL | — | — |
| 192.42.118.0/23 | 512 |
1.8%
|
SURF B.V. | NL | — | — |
| 185.17.73.0/24 | 256 |
17.6%
|
SURF B.V. | NL | — | — |
| 185.100.59.0/24 | 256 |
98.8%
|
SURF B.V. | NL | — | — |
| 192.12.54.0/24 | 256 |
9.4%
|
SURF B.V. | NL | — | — |
| 192.16.200.0/24 | 256 |
0.0%
|
SURF B.V. | NL | — | — |
| 192.42.117.0/24 | 256 |
1.6%
|
SURF B.V. | NL | — | — |
| 192.150.94.0/24 | 256 |
14.8%
|
SURF B.V. | NL | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS1101 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 |
|---|---|---|
| 145.102.4.0/23 | 66,518 | 2026-11-08 20:58:07 |
| 44.137.0.0/16 | 66,108 | 2026-11-08 20:58:07 |
| 192.12.54.0/24 | 64,872 | 2026-11-08 20:58:25 |
| 145.99.0.0/16 | 64,165 | 2026-11-08 20:58:07 |
| 192.42.118.0/23 | 58,540 | 2026-11-08 20:58:10 |
| 185.17.73.0/24 | 57,273 | 2026-11-08 20:58:06 |
| 145.220.0.0/16 | 49,958 | 2026-11-08 20:58:07 |
| 145.192.0.0/12 | 49,031 | 2026-11-08 20:58:07 |
| 145.208.0.0/13 | 48,884 | 2026-11-08 20:58:07 |
| 185.100.59.0/24 | 47,851 | 2026-11-08 20:58:07 |
| 192.42.128.0/22 | 47,442 | 2026-11-08 20:58:07 |
| 192.42.117.0/24 | 46,130 | 2026-11-08 20:58:07 |
| 192.150.94.0/24 | 45,450 | 2026-11-08 20:58:07 |
| 192.16.200.0/24 | 45,312 | 2026-11-08 20:58:07 |
| 145.216.0.0/15 | 38,542 | 2026-09-21 13:04:44 |
| 192.42.118.0/24 | 12,937 | 2026-11-08 20:58:07 |
| 192.42.119.0/24 | 12,922 | 2026-11-08 20:58:07 |
| 145.111.0.0/16 | 1,227 | 2026-09-24 12:51:14 |
| 145.102.131.0/24 | 609 | 2026-09-01 16:50:26 |
Frequently Asked Questions
What is AS1101?
AS1101 is an Autonomous System Number assigned to SURF B.V.. 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 AS1101 announce?
AS1101 announces 1.90M IPv4 addresses distributed across 15 routed CIDR prefixes. The network is registered in The Netherlands.
Who operates AS1101?
AS1101 is operated by SURF B.V.. The organization is based in The Netherlands. You can view all IP ranges and related ASNs on the organization page.
What country is AS1101 registered in?
AS1101 is registered in The Netherlands. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
