WHOISIP Tools
Identify, locate, and check the reputation of any IP address.
What are IP tools?
IP tools explain what is publicly known about an internet address. Every device and server online is reached through an IP address, and these addresses carry useful context: which network announces them, which registry allocated them, whether they have a reverse DNS name, and whether they appear on spam block lists. The IP tools on this page read that public data for IPv4 and IPv6 addresses, and one of them helps you plan address ranges of your own.
None of them can find a person or a street address, because that information is not public.
What each IP tool does
IP Lookup classifies an address as public, private or special-use and, for public addresses, shows its ASN, network name, routed range, registry country, PTR hostname and block list status.
What Is My IP? shows the public address your own connection is using right now, with its provider, network range and reverse DNS name. There is nothing to type.
IP WHOIS focuses on registry data: which of the five regional internet registries handles the block, the operator, the ASN, the allocation date and the registry WHOIS server to ask for the full record.
IP Blacklist Checker checks an IPv4 address against three DNS-based block lists, SpamCop, Barracuda and SORBS, and shows a separate result for each.
CIDR Calculator works out the network address, masks, broadcast address, host counts and first and last usable addresses for any IPv4 or IPv6 block.
Reverse IP Lookup finds the PTR hostname recorded for an address, or for the address a domain points to.
When to use which IP tool
Investigating an unfamiliar address
Start with IP Lookup for the overall picture. If you need to contact the network about abuse, IP WHOIS names the registry and its WHOIS server, where the abuse contact is listed.
Checking your own connection
What Is My IP? confirms which address and provider websites see, which is useful for VPN checks and firewall allow-lists. Switching from Wi-Fi to mobile data changes the address too.
Email delivery problems
Run the sending server's address through the IP Blacklist Checker, then use Reverse IP Lookup to confirm it has a PTR record, which many receiving mail servers expect.
Planning a network
The CIDR Calculator shows how many devices a subnet can hold and which addresses are usable before you configure anything.
Public and private addresses
Some ranges are reserved for local networks, such as 10.0.0.0/8, 172.16.0.0/12 and 192.168.0.0/16, and others for special purposes such as loopback. IP Lookup labels these instead of looking them up, because they are not unique on the internet and have no public owner, network or reputation. Only public addresses get network, registry and block list details.
Problems these IP tools help solve
- An unknown address appears in server logs or login alerts.
- Messages from your mail server are rejected or filtered.
- A firewall rule needs the exact range a provider uses.
- A VPN might not be hiding your real address.
- A new subnet needs the right size for the number of devices.
- A mail server needs a reverse DNS name before it can send reliably.
Related categories
Addresses rarely matter on their own. DNS Tools show which addresses a domain points to, Email Tools check mail server reputation and authentication, and Website Tools test the server running at an address.
Frequently asked questions
Can IP tools find someone's location?
Only roughly. They show the network that announces an address and the country where its block is registered. They never show a street address or a person's name. Internet providers keep customer assignments private and share them only under legal process, so no public tool can reveal them.
What is the difference between IP Lookup and IP WHOIS?
IP Lookup gives a broad overview: address type, network, routed range, reverse DNS and block list status. IP WHOIS concentrates on registry information, such as the regional registry, operator and allocation date, and names the registry WHOIS server where the full record and abuse contacts can be found.
Do the IP tools support IPv6?
Yes, for IP Lookup, IP WHOIS, Reverse IP Lookup, the CIDR Calculator and What Is My IP?. Block list checks are IPv4 only, because block list coverage for IPv6 is inconsistent between providers and results would not be reliable enough to show.
Why does my IP address show a different country?
The country comes from where the address block is registered, not from GPS. Mobile networks and VPNs often route traffic through other cities or countries, and large providers register blocks centrally and use them worldwide. The provider name is usually a better guide than the country.
Which block lists does the IP Blacklist Checker use?
It checks the SpamCop Blocking List, the Barracuda Reputation Block List and SORBS. Each result is shown separately as listed, not listed or unable to check. Spamhaus is not included because its terms restrict use by public web tools, so this is a spot check rather than a full report.
Does Reverse IP Lookup show all sites on a server?
No. It finds the reverse DNS name recorded for one address, which usually belongs to the hosting provider or the server rather than any one website. Listing every site on a shared server would need a crawled database, which these tools do not use.