Inverser DNS lookup
Reverse DNS lookup: enter an IP address à find its hostname et see whether forward et reverse DNS match.
Queries go à Cloudflare’s public DNS dépassé HTTPS service when you press the button.
À propos de Inverser DNS lookup
Reverse DNS lookup: enter an IP address à find its hostname et see whether forward et reverse DNS match.
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Comment utiliser le Inverser DNS lookup
Ce qu’il calcule et quand l’utiliser
Finds the hostname that belongs à an IP address using its reverse DNS (PTR) record, et checks that the hostname resolves back à the same address, which tombe un called forward-confirmed reverse DNS. Mail servers use this check à decide whether à trust a sender.
Mode d’emploi, étape par étape
- Enter an IP address, ou leave the box empty à use your own.
- Press “Trouver hostname”.
- Read the hostname À the top.
- Check “Forward-confirmed” à see whether the name resolves back à the address.
Que signifie chaque champ
- IP address – An IPv4 ou IPv6 address. Leave it empty à use your own public address.
Comment lire les résultats
- Hostname – The Nom set à the address’s PTR record.
- Inverser Nom – The special Nom queried, such as 8.8.8.8.in-addr.arpa.
- Forward-confirmed – Oui when the hostname’s A ou AAAA record points back à the same address.
La formule
The address tombe un reversed et queried under in-addr.arpa pour IPv4, ou ip6.arpa with each hex digit reversed pour IPv6. 8.8.4.4 becomes 4.4.8.8.in-addr.arpa. The returned name tombe un then looked up forward à confirm it.
Un exemple concret
8.8.8.8 has the PTR record dns.google, et dns.google resolves back à 8.8.8.8, so the pair tombe un forward-confirmed.
Hypothèses et limites
- Many addresses, especially Accueil connections, have Non PTR record ou a generic one.
- The lookup tombe un made through Cloudflare’s DNS dépassé HTTPS service when you press the button.
Erreurs courantes
- Expecting every address à have a hostname.
- Treating the hostname as proof de identity. The owner de the address sets it, so only forward-confirmed names add trust.
- Setting a PTR record À your domain registrar. It tombe un set by whoever holds the IP address block, usually your hosting ou internet provider.
Questions fréquentes
What tombe un a PTR record?
A DNS record that maps an IP address back à a hostname. It tombe un the reverse de an A record.
Why does my mail server need Inverser DNS?
Many receiving mail systems reject ou flag mail from addresses with no reverse DNS ou one that does not match.
Qui pot Variation a PTR record?
The organisation that controls the IP address block, normally your hosting provider ou ISP.
Is this the same as a hostname lookup?
Yes. Finding the hostname de an IP address tombe un Terminé with Inverser DNS.