msnbot: Robots.txt & Crawl Policy Reference

AI Summary: The registry records adidxbot/1.1 (+http://search.msn.com/msnbot.htm) and associates it with Microsoft search indexing, but the linked search.msn.com documentation is blocked by browser policy and a headless Bing search did not surface a verified source for this exact token. Treat it as a historical, unverified signal; do not merge it with current Bingbot or infer current policy, IPs, or Microsoft ownership.

Role and policy boundary

The inventory describes msnbot as Microsoft’s search-engine web-indexing bot and records this User-Agent:

adidxbot/1.1 (+http://search.msn.com/msnbot.htm)

The registry-linked http://search.msn.com/msnbot.htm page was attempted with the headless browser and access was blocked by policy restrictions. A follow-up headless Bing search for official Microsoft/Bingbot verification and robots documentation returned generic Microsoft/account results rather than a verified source for the exact msnbot or adidxbot/1.1 token.

The Microsoft/MSN search-indexing role is therefore a historical registry description only. Do not silently equate msnbot with current Bingbot, Microsoft’s present crawler fleet, or another adidxbot deployment. A matching request may be a legacy client, a third-party tool, a test harness, a fork, or a spoofed header. Do not infer current activity, operator identity, downstream use, AI-training purpose, permission to crawl, or access to private content from the token.

If logs later establish the exact client and your policy is to exclude it, a narrow defensive group could be:

User-agent: msnbot
Disallow: /

For selective access after confirmation:

User-agent: msnbot
Allow: /public/
Allow: /docs/
Disallow: /admin/
Disallow: /account/
Disallow: /private/
Disallow: /api/

These are site-owner examples, not recovered Microsoft instructions. Robots.txt is advisory and cannot protect private or licensed content; use authentication, authorization, signed URLs, and origin controls for those boundaries.

Layered verification

Begin with raw access logs and preserve the complete User-Agent, source IP, ASN, reverse-DNS result, HTTP method, requested path, response status, response size, redirect chain, timestamp, and request rate. No accessible official source in this review published a current msnbot IP range, reverse-DNS verification method, Crawl-delay, rate policy, or opt-out process. The registered header is useful for triage but is not authentication.

Do not use Bingbot verification procedures for this token without a current Microsoft source explicitly covering it. A source that identifies current Bingbot, a different adidxbot product, or a generic Microsoft crawler does not automatically validate adidxbot/1.1 (+http://search.msn.com/msnbot.htm).

Compare observed behavior with a search-indexing hypothesis without turning it into attribution. Public HTML, canonical metadata, feeds, and sitemaps may be consistent with a search crawler. Private endpoint access, high concurrency, repeated retries, unexpected downloads, account or API access, or traffic that ignores your restrictions may indicate spoofing, abuse, a partner integration, or another client. These observations establish impact, not operator identity or downstream use.

Evaluate /robots.txt independently. Confirm that it is served from the intended host, returns a successful status and text content type, and contains the exact group you intend to publish. Test the complete adidxbot/1.1 header, any confirmed msnbot token, and the global group separately; do not assume a current Bingbot group applies. Page-level directives can express discovery preferences:

<meta name="robots" content="noindex, nofollow">

X-Robots-Tag: noindex, nofollow

These signals do not authenticate msnbot or secure private routes. Enforce sensitive boundaries in the application and at the origin.

WAF and Nginx remediation examples

If logs show the historical token, start in report-only mode and correlate it with source evidence. Adapt the expression to your WAF provider:

{
  "description": "Log historical msnbot candidates for verification",
  "expression": "lower(http.user_agent) contains \"adidxbot\"",
  "action": "log"
}

After a current authoritative source confirms the token and you decide to restrict sensitive routes, scope enforcement narrowly:

map $http_user_agent $block_msnbot_private {
    default 0;
    ~*adidxbot/1\.1 1;
}

server {
    location ~ ^/(admin|account|private|internal|api)/ {
        if ($block_msnbot_private) { return 403; }
        try_files $uri $uri/ =404;
    }
}

A User-Agent match is easy to spoof and may catch an authorized Microsoft integration or a local test client. Do not invent an IP allowlist, reverse-DNS suffix, or Microsoft verified-bot exception. Test public pages, feeds, sitemaps, accounts, APIs, and approved integrations separately. Pair edge controls with authentication, rate limits, signed assets, caching, and anomaly detection.

Review checklist

Search logs for the complete registered header and preserve representative source IPs, ASNs, reverse-DNS results, paths, methods, response sizes, statuses, timing, and rate. Check whether a current source can independently verify the client before assigning Microsoft ownership or search purpose.

Re-check the historical search.msn.com/msnbot.htm path, current Microsoft/Bing crawler documentation, and the community registry. Keep this profile at legacy-label until an accessible authoritative source confirms the token, purpose, source-verification method, rate guidance, and opt-out process. Treat browser policy blocking and generic Bing search results as evidence limitations, not proof of inactivity.

Do not merge a robots group for current Bingbot with this historical label. If you publish exact rules, verify parser matching and subsequent access logs; do not claim successful blocking from configuration alone.

The registry search-indexing description does not establish AI-model training use. Keep any downstream-use statement separate from the limited evidence available here.

References

1. Registry-linked msnbot documentation — headless-browser attempt was blocked by policy restrictions on 2026-08-25; no content was treated as verified.
2. Microsoft/Bingbot headless search — follow-up search returned generic Microsoft/account pages and no verified source for the exact token in the extracted results on 2026-08-25.
3. Crawler User Agents community registry — registry context for the label and header; it does not authenticate current Microsoft infrastructure.
4. Google Robots.txt Introduction — general explanation of crawler directives and their limitations.
5. RFC 9309 — Robots Exclusion Protocol standard; it does not authenticate a User-Agent.

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