AI crawlers · SEO and research crawlers

`AdIdxBot`

AdIdxBot is the tool or developer fetch run by Microsoft: Microsoft Ads. Its operator documents how to verify it: reverse DNS to search.msn.com, then forward DNS back to the same address. A reverse DNS lookup on the source address must return the operator's domain, and a forward lookup on that name must return the same address.

User-agent token	`AdIdxBot`
Operator	Microsoft
What it does	Microsoft Ads
Kind	tool or developer fetch
Can a request be verified?	Yes — reverse dns
Verification source	reverse DNS to search.msn.com, then forward DNS back to the same address
In a CrawlCheck scan	Read from robots.txt; reported, never scored

Allow or block it in robots.txt

User-agent: AdIdxBot
Disallow: /

User-agent: AdIdxBot
Allow: /

Add a group that names it: "User-agent: AdIdxBot" followed by "Disallow: /". A crawler follows only the most specific group that names it, so once a group names AdIdxBot, rules under "User-agent: *" no longer apply to it; repeat in that group any Disallow lines you still want.

What blocking it changes

No. It is a third-party tool's crawler. Blocking it changes what that tool knows about your site, not anyone's AI answers.

Other agents from Microsoft

bingbot — Bing / Copilot
BingPreview — Bing page preview
msnbot — Microsoft legacy crawler
Copilot-User — Microsoft Copilot fetch

See what AdIdxBot and every other named agent receive from your own site: run a free scan. The full catalogue is on AI crawlers and as JSON at /ai-crawlers.json.

Questions about AdIdxBot

QHow do I block AdIdxBot in robots.txt?

QHow can I tell if a request from AdIdxBot is real?

Its operator documents how to verify it: reverse DNS to search.msn.com, then forward DNS back to the same address. A reverse DNS lookup on the source address must return the operator's domain, and a forward lookup on that name must return the same address.

QDoes blocking AdIdxBot affect whether my site appears in AI answers?

No. It is a third-party tool's crawler. Blocking it changes what that tool knows about your site, not anyone's AI answers.

QDoes CrawlCheck test my site as AdIdxBot?

Not as a request. CrawlCheck reads the rules your robots.txt sets for AdIdxBot and reports them. Rules for it are reported and never scored, because refusing it is a policy choice.