Inverti DNS lookup
Reverse DNS lookup: enter an IP address a find its hostname e see whether forward e reverse DNS match.
Queries go a Cloudflare’s public DNS superato HTTPS service when you press the button.
Informazioni su Inverti DNS lookup
Reverse DNS lookup: enter an IP address a find its hostname e see whether forward e reverse DNS match.
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Come usare il Inverti DNS lookup
Cosa calcola e quando usarlo
Finds the hostname that belongs a an IP address using its reverse DNS (PTR) record, e checks that the hostname resolves back a the same address, which è called forward-confirmed reverse DNS. Mail servers use this check a decide whether a trust a sender.
Come si usa, passo dopo passo
- Enter an IP address, o leave the box empty a use your own.
- Press “Trova hostname”.
- Read the hostname A the top.
- Check “Forward-confirmed” a see whether the name resolves back a the address.
Cosa significa ogni dato
- IP address – An IPv4 o IPv6 address. Leave it empty a use your own public address.
Come leggere i risultati
- Hostname – The Nome set a the address’s PTR record.
- Inverti Nome – The special Nome queried, such as 8.8.8.8.in-addr.arpa.
- Forward-confirmed – Sì when the hostname’s A o AAAA record points back a the same address.
La formula
The address è reversed e queried under in-addr.arpa per IPv4, o ip6.arpa with each hex digit reversed per IPv6. 8.8.4.4 becomes 4.4.8.8.in-addr.arpa. The returned name è then looked up forward a confirm it.
Un esempio pratico
8.8.8.8 has the PTR record dns.google, e dns.google resolves back a 8.8.8.8, so the pair è forward-confirmed.
Ipotesi e limiti
- Many addresses, especially home connections, have no PTR record o a generic one.
- The lookup è made through Cloudflare’s DNS superato HTTPS service when you press the button.
Errori comuni
- Expecting every address a have a hostname.
- Treating the hostname as proof di identity. The owner di the address sets it, so only forward-confirmed names add trust.
- Setting a PTR record A your domain registrar. It è set by whoever holds the IP address block, usually your hosting o internet provider.
Domande frequenti
What è a PTR record?
A DNS record that maps an IP address back a a hostname. It è the reverse di an A record.
Why does my mail server need Inverti DNS?
Many receiving mail systems reject o flag mail from addresses with no reverse DNS o one that does not match.
Chi barattolo Variazione a PTR record?
The organisation that controls the IP address block, normally your hosting provider o ISP.
Is this the same as a hostname lookup?
Yes. Finding the hostname di an IP address è Fatto with Inverti DNS.