Microsoft and Google this month released the IP Ranges used by bots that crawl the web. Webmasters can use the IP addresses to know how their websites are being crawled.

The IP Ranges from Google bots / The IP Ranges from Microsoft bots

The IP Ranges also help the ad programmatic ecosystem to invalidate ad impressions served to crawlers instead of users.

That IP Addresses are now public, it can help servers and CDNs to whitelist them, so Google and Microsoft don't have difficulties crawling websites.