AS203851
CSD Network Services Ltd
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 →
Network profile
Source: PeeringDB →Present at 2 internet exchanges: LINX LON1: Main, LINX LON2
Top CIDR ranges
| CIDR | IPs | PTR Density | Organization | Country | State | City |
|---|---|---|---|---|---|---|
| 185.87.212.0/22 | 1.0K |
16.2%
|
CSD Network Services Ltd | GB | England | Caterham |
| 185.154.50.0/23 | 512 |
0.8%
|
CSD Network Services Ltd | GB | England | Southampton |
| 185.154.50.0/24 | 256 |
1.2%
|
CSD Network Services Ltd | GB | — | — |
BGP Announced Prefixes
Live BGP anomalies →Prefixes AS203851 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 |
|---|---|---|
| 185.87.212.0/24 | 5,235 | 2026-07-29 19:21:52 |
| 185.87.215.0/24 | 5,235 | 2026-07-29 19:21:52 |
| 185.87.214.0/24 | 5,234 | 2026-07-29 19:21:52 |
| 185.154.50.0/24 | 5,228 | 2026-07-29 19:21:52 |
| 185.87.213.0/24 | 5,222 | 2026-07-29 19:21:52 |
| 185.154.51.0/24 | 2,976 | 2026-07-01 21:36:44 |
Frequently Asked Questions
What is AS203851?
AS203851 is an Autonomous System Number assigned to CSD Network Services Ltd. 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 AS203851 announce?
AS203851 announces 1.5K IPv4 addresses distributed across 3 routed CIDR prefixes. The network is registered in United Kingdom.
Who operates AS203851?
AS203851 is operated by CSD Network Services Ltd. The organization is based in United Kingdom. You can view all IP ranges and related ASNs on the organization page.
What country is AS203851 registered in?
AS203851 is registered in United Kingdom. This indicates where the network operator is headquartered, though the IP addresses it announces may serve users globally.
