https://nmap.org/nsedoc/scripts/fcrdns.html
fcrdns NSE script — Nmap Scripting Engine documentation
How to use the fcrdns NSE script: examples, script-args, and references.
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https://multirbl.valli.org/
MultiRBL.valli.org - Blacklist, Whitelist and FCrDNS check tool
Free multiple DNSBL/RBL lookup and FCrDNS check tool. Test the IP (IPv4 or IPv6) of your mailserver on more than 200 blacklists and whitelists.
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https://powerdmarc.com/fcrdns-record-checker/
FCrDNS Record Checker Lookup | Free DMARC
Jul 23, 2024 - FCrDNS Free Record Lookup checker. Sign up for 15 days free DMARC Trial now.
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