Autonomous system
AS23780 CTB CTB Media Inc.
Unclassified APNIC Cable/DSL/ISP
Summary
CTB Media Inc.
cable isp residential japan
CTB is the AS handle for CTB Media Inc., a Japanese cable and DSL internet service provider.
What it's used for
- The address space carries residential access traffic, evidenced by reverse DNS entries such as
dhcp24-254.ctb.ne.jpandgw00-00-000.ctb.ne.jpacross multiple prefixes. - The AS announces 16,384 IPv4 addresses and 1 IPv6 prefix, with 22 observed routing neighbours, indicating a role as an access network rather than a transit provider.
Notable
- All registrants for the announced prefixes are listed as Japan Network Information Center (JPNIC), which is consistent with the holder being a Japanese ISP.
- The address inventory consists of five IPv4 prefixes and one IPv6 prefix, all located in Japan, with netnames
CTB-CIDR-BLK-JPandCTBreflecting the operator's identity.
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
Recorded at 5 exchanges in 3 countries, largest first.
| Exchange | Location | Their address |
|---|---|---|
| BroadBand Internet eXchange Tokyo | Tokyo, Japan | 101.203.88.100 |
| JPIX Tokyo | Tokyo, Japan | 210.171.224.191 |
| BroadBand Internet eXchange Singapore | Singapore, Singapore | 103.231.152.124 |
| BroadBand Internet eXchange Osaka | Osaka, Japan | 218.100.9.136 |
| BroadBand Internet eXchange Hong Kong | Hong Kong, China | 103.203.158.124 |
Transit providers
9 upstream, 0 downstream and 14 adjacent networks observed; most-used upstreams first.
Exchange presence is recorded rather than inferred: the directory collected by Packet Clearing House (https://www.pch.net/ixp/data) on 2026-10-10, licensed CC BY-NC-SA 3.0. Transit is inferred from observed BGP paths, never declared by either party.
Address space
Summary
IPv4 5 prefixes · 16.38K addresses IPv6 1 prefixes
| Country | Name | Prefixes |
|---|---|---|
| JP | Japan | 6 |
Registry
Allocation record
- Registry
- APNIC
- Handle
AS23780- Registry name
- CTB
- Abuse contact
- hostmaster@nic.ad.jp
- Registered
- 2003-06-16
- Last changed
- 2003-08-13
- Allocation
- allocated
Declared
PeeringDB profile
- Name
- CTB Media Inc.
- Also known as
- CTB
- Network type
- Cable/DSL/ISP
- Scope
- Asia Pacific
- Traffic ratio
- Mostly Inbound
- Peering policy
- Open
- IRR as-set
AS-23780- Present at
- 10 exchanges
- Facilities
- 2 facilities
- Website
- https://www.ctb.jp
PeeringDB records are maintained by the network operator and are not independently verified. Treat them as a statement of intent rather than of fact. For the observed and recorded view, see peering, which lists the exchanges Packet Clearing House has a port on file for.
Routing security
RPKI and IRR
- RPKI
- 83% valid · 5 valid, 1 with no ROA
- ROAs
- 5 authorising AS23780
- ASPA
- no ASPA record
- IRR
- 83% registered · 5 of 6 announcements
- Route objects
- 5 naming AS23780
Reputation
Classification and threat
Unclassified Not in the curated lists. Most of the ~80,000 allocated ASNs are not.
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: 431 networks and 1,775 prefixes, as published 2026-10-11. 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