Data as of Nov 4, 2026
173.251.54.0/24
No anonymizer space · no proxy exits in 30 daysEisai Inc. · space held by Cablevision Systems Corp.
Announcements
Less specific
Covering announcements
| Prefix | Origin | Type | Proxy exits | Holder | RPKI |
|---|---|---|---|---|---|
| 173.251.0.0/17 since Jul 2010 | AS6128 | Residential | 42 6 always on | Cablevision Systems Corp. |
Registrations in this block
The registry's network records over the announcement: those covering it, widest first, then every record inside it, under its parent.
| Range | Addresses | Netname | Holder | Type | Created | Abuse contact |
|---|---|---|---|---|---|---|
| 173.251.0.0/17 | 32,768 | CVNET-2 | Cablevision Systems Corp. (CVNT) · US | Direct Allocation | Jun 18, 2010 | [email protected] |
| └ 173.251.54.0/24 | 256 | CVNET-ADFB3600 | Eisai Inc (C06953899) · US | Reassigned | Apr 13, 2018 | [email protected] via CVNET-2 |
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
Registry
Holder
- Organization
- Cablevision Systems Corp.
- Handle
- CVNT
- Range
- 173.251.0.0/17
- Registration type
- Direct Allocation
- Record created
- Jun 18, 2010
Origin network
AS13599
US
- Name
- Eisai Inc.
- Type
- Business
- Registered
- Oct 27, 2015
- Domain
- eisai.com
- Industry
- Chemical and Pharmaceutical Manufacturing
- Spamhaus ASN-DROP
- not listed
Routing timeline
Covering aggregate above, the prefix's own history below
Summary
Routing history
- Pattern
- Stable
- First seen
- Dec 2010
- Current origin since
- May 2023 · 3.5 yr
- Origin networks
- 1
RPKI
Route origin authorizations
| ROA prefix | ASN | Max len | Anchor | Verdict |
|---|---|---|---|---|
| 173.251.54.0/24 | AS13599 | /24 | ARIN | RPKI valid |
| 173.251.0.0/17 | AS6128 | /24 | ARIN | Another network |
IRR
Route objects on the exact prefix
| Origin | Registry | Description | Maintainer | Modified |
|---|---|---|---|---|
| AS13599 | RADB | Eisai Inc. | MAINT-AS27506 | Sep 3, 2025 |
Whois
Registration for this announcement
- Range
- 173.251.54.0/24
- Netname
- CVNET-ADFB3600
- Registrant
- Eisai Inc
- Organization
- Eisai Inc (C06953899)
- Type
- Reassigned
- Handle
- NET-173-251-54-0-1
- Parent
- NET-173-251-0-0-1
- Created
- Apr 13, 2018
- RIR
- ARIN
- Country
- US
- Delegated
- Jun 18, 2010
- Status
- assigned
Report abuse
Abuse contact
- [email protected]
- Name
- OOL Hostmaster
- Phone
- +1-516-803-2400
- Handle
- OOLAB-ARIN