Data as of Nov 7, 2026
81.23.241.0/24
No anonymizer space · no proxy exits in 30 daysCastor Marine B.V.
Registrations in this block
The registry's network records over this block, widest first, each under its parent.
| Range | Addresses | Netname | Holder | Type | Created | Abuse contact |
|---|---|---|---|---|---|---|
| 81.23.240.0/23 | 512 | NL-CASTOR-20021105 | Castor Marine B.V. (ORG-CHB2-RIPE) · NL | ALLOCATED PA | Apr 16, 2021 | abuse@ |
| └ 81.23.241.0/24 | 256 | NL-CASTOR-IDIRECT | unknown | ASSIGNED PA | Apr 16, 2021 | abuse@ via NL-CASTOR-20021105 |
A contact marked “via” is the registry's: the record names none of its own, so the registry hands down its parent's.
Network & registry
Announced by
Covering announcement 81.23.240.0/23
- Prefix
- 81.23.240.0/23
- Announced by
- AS61429 Castor Marine B.V.
- Type
- Internet provider
- RPKI
- RPKI valid
- Netname
- NL-CASTOR-20021105
- Registrant
- Castor Marine B.V.
- RIR
- RIPE NCC
Origin network
AS61429
NL
- Name
- Castor Marine B.V.
- Type
- Internet provider
- Registered
- Oct 12, 2012
- Domain
- castornetworks.com
- Industry
- Internet Service Provider (ISP)
- Spamhaus ASN-DROP
- not listed
Routing timeline
Who has announced 81.23.240.0/23
81.23.240.0/23
Routing history
- Pattern
- Stable
- First seen
- Mar 2020
- Current origin since
- May 2021 · 5.5 yr
- Origin networks
- 2
- Last change of origin
- May 2021
Recorded history
History
- Handoffs
- 1
RPKI
Route origin authorizations
| ROA prefix | ASN | Max len | Anchor | Verdict |
|---|---|---|---|---|
| 81.23.240.0/23 | AS61429 | /23 | RIPE | RPKI valid |
IRR
Route objects on 81.23.240.0/23
| Origin | Registry | Description | Maintainer | Modified |
|---|---|---|---|---|
| AS61429 | RIPE | Castor Holding B.V. | CASTOR-MNT | Aug 12, 2025 |
Whois
Registration for this announcement
- Range
- 81.
23. 240. 0/ 23 - Netname
- NL-CASTOR-20021105
- Registrant
- Castor Marine B.V.
- Registrant country
- NL
- Organization
- Castor Marine B.V. (ORG-CHB2-RIPE)
- Org country
- NL
- Type
- ALLOCATED PA
- Created
- Apr 16, 2021
- Updated
- Aug 12, 2025
- Maintainer
- RIPE-NCC-HM-MNT
- RIR
- RIPE NCC
- Country
- NL
- Delegated
- Nov 5, 2002
- Status
- assigned
Report abuse
Abuse contact
- abuse@
castornetworks. com - Name
- Abuse-C Role
- Handle
- AR54144-RIPE