https://dnslytics.com/
Online investigation tool - Reverse IP, NS, MX, WHOIS and Search Tools
DNSlytics provides the ultimate online investigation tool. See detailed information about every IP address, domain name and provider. Perform network tests...
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https://reverse-ns.whoisxmlapi.com/lookup
Reverse NS Lookup is a reverse nameserver lookup tool | WhoisXML API
Access NS reverse lookup reports with the complete list of domain names that share the same nameserver you specify. Get started today with free credits.
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https://www.prepostseo.com/reverse-ns-checker
Reverse NS Checker
Reverse NS Checker gives you the complete list of domains that uses those name servers.
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