Resolved over DNS, not read from headers

Which networks refuse AI crawlers

A server can decline to say who runs it. It cannot decline to have an address. Every domain here was resolved to an IP, the IP mapped to its autonomous system, and the refusal rate computed per operator - so the figure covers origins that strip every identifying header.

The measurement

Origin networks were resolved for 30,030 of 30,345 measured domains, against 7,804 identifiable from response headers alone. Among networks hosting at least 50 measured domains, SERVICEPIPE has the highest refusal rate at 72% of 74 domains, against 22.0% across all resolved networks.

Measured 2026-08-25 by direct request to every domain in the corpus. Method: how this is measured. Reuse under CC BY 4.0 with attribution.

Cite as: Crawl Census, "AI crawler refusal by origin network", measured 2026-08-25. https://crawlcensus.com/networks

30,030
domains resolved to a network
7,804
identifiable from headers alone
3.8x
coverage gained
29
networks with 50+ domains

Refusal rate by origin network 25 or more domains each

bar chartSERVICEPIPE71.6%Automattic37.5%Cloudflare36.1%Akamai27.2%Datacamp17.9%Google13.8%Renater13.7%Amazon12.5%Verein zur Foerderung ein…11.4%Fastly11.4%DigitalOcean10.9%Microsoft9.9%OVH7.4%Hetzner7.3%

Every network measured the table

NetworkASNDomainsRefuse AI agentsRateCharge instead
SERVICEPIPEAS201706745372%-
AutomatticAS263528810838%22
CloudflareAS133358,9033,21436%114
AkamaiAS1662581922327%1
DatacampAS60068671218%-
GoogleAS1516985511814%-
RenaterAS78951714%-
AmazonAS89876,12576312%54
Verein zur Foerderung eines Deutschen FoAS68079911%-
FastlyAS541131,09212411%62
DigitalOceanAS140611651811%-
MicrosoftAS80686746710%1
OVHAS16276351267%-
HetznerAS24940453337%1
DDOS-GUARDAS57724156117%-
OracleAS318985747%-
ImpervaAS19551329227%-
DataWeb Global GroupAS3957212387%-
Alibaba (US) TechnologyAS45102154106%-
Cloudflare LondonAS209242681436%-
Yandex.CloudAS2003508056%-
Optimizely ABAS308115036%-
Shenzhen Tencent Computer Systems CompanAS450906946%-
HLLAS5111515085%-
IDCAS237245835%-
JSC SelectelAS4950515464%-
Hangzhou Alibaba AdvertisingAS3796320063%-
IONOS SEAS85605412%-
F5 Networks SARLAS352805200%-

Why this differs from the edge table method

The edge provider table reports what a server says about itself: a server header, a cf-ray, an x-served-by. Roughly three quarters of measured domains say nothing at all, and a header can be forged or stripped.

This page reports something a site cannot suppress. The domain resolves to an address, the address belongs to an autonomous system, and that mapping is published in the global routing table. It answers a different question - not "which CDN is in front of this origin" but "whose network is this origin on" - and for a self-hosted origin those are the same answer, while for a CDN-fronted origin the anycast address belongs to the CDN.

Networks hosting fewer than 50 measured domains are excluded: a refusal rate over a handful of sites is noise. Resolution uses DNS over HTTPS and the Team Cymru IP-to-ASN service, both queried live at scan time.