Microsoft · Search index
msnbot
Dead as a crawler, alive as a verification artifact: that is the whole of it. Bingbot replaced it effective 1 October 2010, retiring what Microsoft's announcement called the “venerable web crawler,” and the name is absent from the present-tense list of crawlers Bing says it operates today. What survived is the hostname convention: Microsoft's current Bingbot verification instructions tell you to confirm that a crawling IP reverse-resolves under `search.msn.com`, and the worked example carried through that document is `msnbot-157-55-33-18.search.msn.com`. So in 2026 this string is reverse DNS attached to live Bingbot infrastructure rather than a user agent any Microsoft crawler sends, and a genuine-looking `msnbot` UA hit in your logs is a spoof or an ancient scraper, with no vendor mechanism to check either way, because the rDNS and IP tooling Microsoft publishes is scoped to Bingbot.
- Operated by
- Microsoft
- Purpose
- Search index
- robots.txt token
- msnbot
- Verification
- Not sent as a user agent
Crawls continuously to build and refresh an AI search index.
Can msnbot be verified?
No. Microsoft operates no crawler that sends msnbot as a user agent, so there is no genuine request for a check to confirm. Anything you see in your logs carrying this name is something else, and Microsoft publishes no way to tell what, because the verification tooling it does publish covers the crawlers it actually runs and says nothing about this name. This page therefore offers no method for verifying msnbot; the robots.txt directive below is still worth reading, because a rule written under this name can still have an effect.
No request carries this name, so there is nothing to confirm. This entry was last reviewed against Microsoft's own documentation on .
User agent
None in current use. Microsoft publishes no user-agent string for msnbot because it operates no crawler that sends one. The name does still turn up in access logs, and that is worth knowing rather than matching on: whatever sends it is not Microsoft's crawler, and nothing Microsoft publishes will tell you what it is.
robots.txt for msnbot
Historically yes, and the compatibility rule was published rather than assumed: Bing “will still honor all applicable robots.txt directives, including those specific to MSNBot,” but as of 1 October 2010, where a robots.txt file carries separate custom directives for both MSNBot and BingBot, the BingBot directives take precedence.
Block
User-agent: msnbot
Disallow: /Allow
User-agent: msnbot
Allow: /robots.txt is a request, not an enforcement mechanism. It is honoured by convention, and a crawler that ignores it is stopped at your edge, not in a text file.
What blocking msnbot costs you
Nil in the forward direction, since there is nothing left to refuse. The risk runs backwards instead: Microsoft has honoured msnbot directives as applying to Bing since 2010, so a decade-old `Disallow` sitting under this name in robots.txt can still suppress Bing crawling today, unless a bingbot-specific rule exists, which takes precedence where both are present. Anyone maintaining a long-lived robots.txt should audit for that rather than assume the rule went inert when the crawler did.
Vendor documentation
Microsoft does not publish documentation for msnbot that we could find. Everything on this page comes from what they do publish elsewhere and from observed behaviour, so treat it accordingly.