WILLIAM BLAIR INTERNATIONAL, LTD
William Blair
Data as of 2026-09-13
GLEIF verified
Limited data: only 3 ranges found registered
under this exact name. This may not reflect the organisation's full internet footprint — many companies'
web and cloud infrastructure is hosted under a third-party provider's own registration rather than their own.
LEI
213800D836LM6FFK9U60
Registered name
WILLIAM BLAIR INTERNATIONAL, LTD
Jurisdiction
Ultimate parent
No parent on file in GLEIF
This organisation
| Netblocks | 3 · 264 IPv4 addresses |
| IPv6 | 1 prefix (largest 2a00:2381:df1::/48) |
| Record ID | 243194908 |
| Registry | ARIN |
| Owner jurisdiction | GB |
| Customers | see who runs inside this network → |
Evidence & provenance ?
| Attribution | GLEIF legal-entity match |
| Legal identity | LEI 213800D836LM6FFK9U60 |
| Shared handles | clustered on 8 shared RIR contact/maintainer handles |
| Registry names | 3 distinct registrant names across these blocks |
| full provenance (JSON) → · how attribution works · report an issue | |
IP Ranges (3)
⬇ export CSV| CIDR | Org name | Registry | Status | Confidence |
|---|---|---|---|---|
| 199.103.106.0/24 | William Blair | ARIN | DIRECT ALLOCATION | ● high |
| 213.161.93.80/29 | Net-William-Blair-International-LTD | RIPE | ASSIGNED PA | ● low |
| 2a00:2381:df1::/48 | WILLIAM-BLAIR-CO-LLC | RIPE | AGGREGATED-BY-LIR | ● low |
IPv6 ranges (1)
| CIDR |
|---|
| 2a00:2381:df1::/48 |
Network trust
what's this?
RPKI hygiene: C
how networks compare →
66.7%
of checked blocks have valid RPKI ROA coverage
(2 of 3)
Possible discrepancies (1)
These blocks are registered to William Blair but cryptographically authorized for a different, unrelated network (1 distinct holder) — often M&A history, multi-homing, or outsourced/managed hosting, occasionally worth a closer look.
| 2a00:2381:df1::/48 /48 | authorized for AS2856 — British Telecommunications Limited |
NIC Handles
ABOVENET-MNT
BTNET-MNT
DUMY-RIPE
DUMY-RIPE
MH161-ARIN
MH161-ARIN
MH161-ARIN
WILLIA-4