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IP Lookup

Look up basic technical information about an IP address, including IP version, classification and reverse DNS where available.

This is a technical lookup: IP version, address classification and any reverse DNS hostname published for the address. It is not geolocation — it does not estimate where an address is located or who is using it.

Education Host runs your lookup for this request only. It is not stored in a database by this tool, although normal server and security logs may record requests like any other website.

The basics

What information can an IP lookup show?

An IP lookup shows technical facts about an address: whether it is IPv4 or IPv6, whether it is public or belongs to a private/reserved range, and any reverse DNS hostname the network operator has published.

It deliberately does not show location or identity. Geolocation databases vary in accuracy and this tool does not use them.

What the lookup covers

  • IP version — IPv4 or IPv6
  • Classification — public, private, loopback, link-local or unique local
  • Reverse DNS (PTR) hostname, where one is published
  • What it does not show — location, owner identity or account details
Address ranges

Public vs private IP addresses

Public addresses are routable on the internet and are what websites and mail servers see. Private and reserved ranges only exist inside local networks and are reused everywhere — millions of networks have a 192.168.1.1.

  • Private IPv4 — 10.x.x.x, 172.16–31.x.x and 192.168.x.x
  • Loopback — 127.x.x.x and ::1, the machine talking to itself
  • Link-local — 169.254.x.x and fe80::, used within one network segment
  • Unique local IPv6 — fc00::/7, the IPv6 equivalent of private ranges
  • Everything else that validates is a public address
Reverse DNS

What is reverse DNS?

Reverse DNS maps an IP address back to a hostname using PTR records, which are controlled by whoever operates the network the address belongs to.

Many addresses have no PTR record at all — that is normal. Where reverse DNS matters most is email: receiving servers often expect a sending IP's PTR record to exist and match its mail server name.

Reverse DNS in brief

  • Set by the network operator, not the domain owner
  • Optional — many addresses publish none
  • Checked by mail servers when receiving email
  • One address can occasionally map to several hostnames
More tools

Related tools

Part of a growing set of free Education Host checks — with more on the way.

IP Address Checker

See the public IP address your browser is using to reach this website.

Check your IP address

DNS Checker

Check DNS records for a domain, from A and MX to TXT, CAA and PTR.

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Blacklist Checker

Check whether an IP address appears on common DNS-based email blacklists.

Check blacklist status

DMARC Checker

Check whether a domain has a DMARC record and review the published policy.

Check a DMARC record

Whois Lookup

Look up public domain registration information where available.

Run a Whois lookup

SSL Certificate Checker

Check SSL certificate issuer, expiry date and common HTTPS details for a domain.

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IP lookup — frequently asked questions

Answers to common questions about IP addresses, classifications and reverse DNS.

What is an IP lookup?
An IP lookup shows technical information about an IP address — its version (IPv4 or IPv6), whether it is public or private, and any reverse DNS hostname published for it.
What is reverse DNS?
Reverse DNS uses PTR records to map an IP address back to a hostname. The network that owns the address controls its PTR record, and mail servers often expect a sending IP to have one that matches its hostname.
Is this the same as IP geolocation?
No. This tool shows technical details only — it does not estimate where an address is located. Geolocation databases exist but vary in accuracy, and this tool deliberately does not include them.
Why does an IP lookup sometimes show no hostname?
Many addresses simply have no PTR record published. That is normal — reverse DNS is optional and set by the network operator, and unused or consumer ranges often go without it.
Can I look up IPv6 addresses?
Yes. The lookup accepts IPv4 and IPv6 addresses, classifies both, and checks reverse DNS for public addresses.
Does Education Host store IP lookups?
This tool runs your lookup for the current request and does not store it in a database. Normal server and security logs may record requests like any other website.