Autonomous system
AS5517 CSL
Hosting RIPE
Summary
CSL Computer Service Langenbach GmbH
hosting legacy
CSL is CSL Computer Service Langenbach GmbH, a German hosting company operating its own datacentre on Hansaallee in Duesseldorf. The company dates to 1972 and has run an internet business since the mid-1990s.
What it's used for
- Managed hosting, root and dedicated servers, private cloud and SSL certificates, all served from CSL's Duesseldorf facility.
- Tens of thousands of domains resolve into this space, the clearest signature of a shared-and-dedicated hosting operator.
Notable
- CSL is also an ICANN-accredited domain registrar, operating the Joker.com registrar brand. That puts registrar, DNS and hosting infrastructure behind the same AS.
- The datacentre is certified by the German Federal Network Agency for its privacy standards, which is part of the pitch: German-hosted, German-regulated.
Interesting
- The low AS number is genuine here rather than a reassignment artifact. CSL has been an internet provider since the mid-1990s, so it belongs to the generation of German operators that got their numbers when the range was still being handed out sequentially.
This description is AI-generated, best-effort context — not authoritative, and provided without any guarantee of accuracy. Source, and how to suggest an edit.
Interconnection
Peering at a glance
Internet exchanges
No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-14, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 3 prefixes · 139K addresses IPv6 1 prefixes
| Country | Name | Prefixes |
|---|---|---|
| DE | Germany | 4 |
Registry
Allocation record
- Registry
- RIPE
- Handle
AS5517- Registry name
- CSL
- Registrant
- CSL-MNT
- Abuse contact
- abuse@nrw.net
- Registered
- 1970-01-01
- Last changed
- 2023-10-30
- Allocation
- allocated
Routing security
RPKI and IRR
- RPKI
- 100% valid · 4 valid, 0 with no ROA
- ROAs
- 4 authorising AS5517
- ASPA
- no ASPA record
- IRR
- 100% registered · 4 of 4 announcements
- Route objects
- 15 naming AS5517
Reputation
Classification and threat
Hosting Datacenter or cloud provider. Addresses are servers, not people.
Spamhaus DROP
Not on ASN-DROP The network as a whole is not listed.
No DROP prefixes None of its announced space is on the DROP prefix list.
Spamhaus DROP ("Don't Route Or Peer") lists space and networks run by, or hijacked for, spam and cybercrime operations: 442 networks and 1,771 prefixes, as published 2026-10-15. A short, high-confidence list, so a match is worth taking seriously, and absence from it says little on its own.
FBI IC3
No IC3 indicators Nothing from the FBI IC3 feed.
IC3 threat data is alpha. Absence of an indicator is not evidence of good behaviour, only of absence from this one feed.
Elsewhere