Free Reverse IP Lookup: see every domain hosted on an IP
What is a reverse IP lookup?
A reverse IP lookup turns an IP address into the list of domains that resolve to it. An ordinary DNS lookup runs one way, from a domain to an address. This runs the other way, so you can see what else shares the same server. The result tells you whether an address serves one site or several hundred, and which company operates the network behind it.
What comes back depends on how the address is used. A dedicated server usually returns a single domain. Shared hosting or a reseller can return hundreds. Some addresses return nothing at all, because no public domain points at them. That variation is normal, and it is worth reading as information about the host rather than as a failed lookup.
How a reverse IP lookup works
When you submit an IP address, the check runs three steps:
- Domain index match: Your address is matched against an index of domain-to-address records, which returns every domain known to resolve to it.
- Network attribution: The lookup adds the ASN that routes the address, the ASN number, the company operating it and the country it sits in, so you know who runs the server as well as what is on it.
- Single-call response: The domain list and the network fields come back together in one request. No separate DNS queries, no per-domain orchestration.
The check matches your address against an index of domain-to-address records, so it can answer the question in reverse. Abstract adds the network layer on top of that list: the ASN that routes the address, the ASN number, the company that operates it and the country it sits in. Most lookups finish in under 200ms.
Reverse IP lookup vs. reverse DNS
Two lookups that sound alike and answer different questions.
Reverse IP lookup (what this tool does) returns the domains hosted on an address. Use it when you want to know what else runs on a server, who operates the network, or whether an address is shared infrastructure.
Reverse DNS returns the single PTR hostname the address owner has published for that address. It is what receiving mail servers check, and it usually reads as a provider hostname rather than a customer domain. One address can host many domains but publishes only one PTR record.
Use this page when you want the hosted-domain list. Use a PTR lookup when you are debugging mail delivery or checking that an address identifies itself consistently.
Use cases for a reverse IP lookup
Shared hosting and neighbour checks: See what else runs on the address serving your site. An address that also hosts spam or adult domains can change how filters and reputation systems treat your traffic.
Security investigation: Pivot from a suspicious address to the domains behind it. Attackers reuse infrastructure, so the other domains on an address often explain what you are looking at.
Vendor and infrastructure mapping: Work out whether a partner runs dedicated infrastructure or sits on shared hosting, and which provider actually operates the address.
Prospect research: Identify the company behind an address and the other properties it runs, so outreach reaches the right organisation.
See what the API returns
Response parameters
ip_address
security.is_vpn
security.is_proxy
security.is_tor
security.is_hosting
security.is_relay
security.is_mobile
security.is_abuse
asn.asn
asn.name
asn.domain
asn.type
company.name
company.domain
company.type
domains.domains
location.city
location.city_geoname_id
location.region
location.region_iso_code
location.region_geoname_id
location.postal_code
location.country
location.country_code
location.country_geoname_id
location.is_country_eu
location.continent
location.continent_code
location.continent_geoname_id
location.longitude
location.latitude
timezone.name
timezone.abbreviation
timezone.utc_offset
timezone.local_time
timezone.is_dst
flag.emoji
flag.unicode
flag.png
flag.svg
currency.name
currency.code
currency.symbol
API Endpoint
curl --request GET \
--url https://ip-intelligence.abstractapi.com/v1API Response
{
"ip_address": "185.197.192.65",
"security": {
"is_vpn": true,
"is_proxy": true,
"is_tor": false,
"is_hosting": false,
"is_relay": false,
"is_mobile": false,
"is_abuse": false,
},
"asn": {
"asn": 136787,
"name": "PacketHub S.A.",
"domain": "packethub.tech",
"type": "isp",
},
"company": {
"name": "PacketHub S.A.",
"domain": "packethub.tech",
"type": "isp",
},
"domains": {
"domains": []
},
"location": {
"city": "Miami",
"city_geoname_id": 4164138,
"region": "Florida",
"region_iso_code": "FL",
"region_geoname_id": 4155751,
"postal_code": "33197",
"country": "United States",
"country_code": "US",
"country_geoname_id": 6252001,
"is_country_eu": false,
"continent": "North America",
"continent_code": "NA",
"continent_geoname_id": 6255149,
"longitude": -80.1946,
"latitude": 25.7689,
},
"timezone": {
"name": "America/New_York",
"abbreviation": "EST",
"utc_offset": -5,
"local_time": "12:07:51",
"is_dst": false,
},
"flag": {
"emoji": "🇺🇸",
"unicode": "U+1F1FA U+1F1F8",
"png": "https://static.abstractapi.com/country-flags/US_flag.png",
"svg": "https://static.abstractapi.com/country-flags/US_flag.svg",
},
"currency": {
"name": "US Dollar",
"code": "USD",
"symbol": "$"
}
}Reverse IP lookup FAQ
How does a reverse IP lookup work?
The check matches your address against an index of domain-to-address records, which lets it answer the question in reverse. You get back the domains found on the address, plus the ASN that routes it, the ASN number, the operating company and the country. Most lookups finish in under 200ms.
Why does my lookup return no domains?
Plenty of addresses host nothing that resolves publicly. CDN edges, mobile carrier ranges and home connections commonly come back empty, and so do servers whose domains are not in the index. An empty result is a finding about the address rather than a failure.
Why does one IP return hundreds of domains?
Shared hosting. A single address can serve many sites, and the web server picks the right one from the hostname on each request. A long list usually points to shared hosting or a reseller, which is useful context when you are judging the address.
Is a reverse IP lookup the same as reverse DNS?
No. Reverse DNS returns the one PTR hostname the address owner published, which mail servers check. A reverse IP lookup returns the domains hosted on the address, which can be none, one or hundreds.
Can I look up several addresses at once?
This tool checks one address at a time and exports its result as a CSV. For a list, the bulk IP lookup tool runs a batch, and the IP Intelligence API handles it with 1,000 free requests a month.
Is the reverse IP lookup tool free?
Yes. The tool is free with no signup for individual lookups. For programmatic access, Abstract's IP Intelligence API offers a free tier with 1,000 requests per month.
How is this different from an IP reputation check?
A reverse IP lookup answers what is hosted on an address. A reputation check answers whether the address itself looks risky, flagging VPN, proxy, Tor, hosting and reported abuse. The two pair well: find the domains here, then judge the address with the IP reputation check.
Does a reverse IP lookup show subdomains?
It shows the domains and hostnames that resolve to the address, so a subdomain appears when it points there directly. A subdomain served through a CDN or a different server will not, because it resolves to a different address.
Where reverse IP lookup fits
The domains on an address tell you what kind of infrastructure you are dealing with.
Want to know whether the address itself looks risky? The IP reputation check returns VPN, proxy, Tor, hosting and reported abuse for the same address.
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