asn.dev

Autonomous system

AS43428 YAHOO-ULS

Unclassified APNIC

IPv4 addresses 768 2 prefixes
IPv6 prefixes 1 counted as prefixes, not addresses
Countries 1 mostly GB
Exchanges 0 recorded by PCH
Upstreams 1 0 downstream
Flagged prefixes 0 none

Summary

Yahoo

United Kingdom · AI-generated

business infrastructure corporate

YAHOO-ULS is operated by Yahoo-UK Limited.

What it's used for

  • The address space carries corporate infrastructure, evidenced by reverse DNS entries such as et18-1.bas3-1-edg.lob.yahoo.com and et51.rsw6-1-edg.lob.yahoo.com, alongside generic unknown.yahoo.com pointers.
  • The AS announces 768 IPv4 addresses across 2 prefixes and 1 IPv6 prefix, with only 1 observed neighbour, indicating a small, self-contained internal estate rather than a transit or access network.
  • Traffic from this AS consists of internal corporate endpoints and edge infrastructure supporting Yahoo's web services and operations in the United Kingdom.

Notable

  • Registrants for both announced prefixes are listed as "Yahoo Europe Operations Department; Network Abuse" under the netname YAHOONET, which aligns with the AS holder.
  • Yahoo-UK Limited is part of the broader Yahoo corporate structure, which has undergone significant ownership changes including its acquisition by Verizon and subsequent integration into Oath (now part of Verizon Media).
  • The inventory is finely subdivided into two small IPv4 blocks and one IPv6 /48, consistent with a segmented internal corporate network.

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

Full topology · Graph

Internet exchanges

No exchange port on file. Many exchanges publish no participant list, so this is not proof of absence.

Transit providers

1 upstream, 0 downstream and 2 adjacent networks observed; most-used upstreams first.

ASNetworkPaths seen
AS10310Yahoo Holdings Inc.218

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

Shape and geography

IPv4 2 prefixes · 768 addresses IPv6 1 prefixes

CountryNamePrefixes
GBUnited Kingdom3

Registry

Allocation record

APNIC · via Atlas (registry + RDAP)
Registry
APNIC
Handle
AS43428
Registry name
YAHOO-ULS
Registrant
Yahoo-UK Limited
Abuse contact
rir-abuse@verizonmedia.com
Registered
2007-07-30
Last changed
2018-09-04
Allocation
allocated

Routing security

RPKI and IRR

Full detail
RPKI
0% valid · 0 valid, 4 with no ROA
ROAs
0 authorising AS43428
ASPA
no ASPA record
IRR
100% registered · 4 of 4 announcements
Route objects
7 naming AS43428

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: 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

Cross-check