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Note that some WHOIS servers (as in port 43) are hostile to automation and might block you if you’re doing it too much, although you could be paying a few cent
by judge2020 4y ago
Note that some WHOIS servers (as in port 43) are hostile to automation and might block you if you’re doing it too much, although you could be paying a few cent per custom domain per month to have a service perform the data aggregation for you.
- ricardo81 4y agoAgree, most ToS of WHOIS servers say they don't want automated queries. In this case I think it'd be simpler to just do a DNS check, either NS alone or A/MX. Scales better. If NXDOMAIN is returned over a period of days then the domain can be flagged.