Google runs several crawlers. The main ones are Googlebot Smartphone (the primary crawler for indexing), Googlebot Desktop, Googlebot Image, Googlebot Video, and separate agents for AdsBot and user-triggered fetches.
Verification matters
User-agent strings are trivially forged. Scrapers routinely claim to be Googlebot to bypass rate limits. Verify with a reverse DNS lookup on the requesting IP, it must resolve to googlebot.com veya google.com, then a forward lookup back to the same IP. Google also publishes its IP ranges as JSON.
Crawl rate
Google adjusts crawl rate automatically based on server response. Consistent 5xx errors or slow responses cause it to back off. There is no longer a manual crawl rate setting in Search Console; if you need to slow it urgently, return 503 or 429, but only briefly, because sustained 5xx responses lead to de-indexing.
Alien Road recommends: verify before you block. We have been called in more than once to fix “Googlebot is hammering the server”, and found a bot-protection rule that was blocking real Googlebot because someone matched on user agent alone. Verify by DNS, allow the real one, and rate-limit the impostors.