Reverse IP Lookup
Discover the hostname associated with any IP address. Query PTR records, ASN information, and network ownership.
Try: 8.8.8.8 (Google DNS) 1.1.1.1 (Cloudflare) 208.67.222.222 (OpenDNS) 9.9.9.9 (Quad9) 185.199.108.153 (GitHub) 104.16.132.229 (Cloudflare)
Reverse Lookup for 9.9.9.9
IP Version: IPv4
Type: Public
Response Time: 51ms
PTR Record (Reverse DNS)
Hostname associated with this IP address
PTR
dns9.quad9.net
Network Information
Autonomous System (ASN) details
| ASN | AS19281 |
| Organization | QUAD9-AS-1 - Quad9, US |
| Country | 🇺🇸 US |
| Registry | arin |
| Allocated | 2017-09-13 |
Queried at 5/10/2026, 8:39:17 PM
About Reverse IP Lookup
Reverse IP lookup (also known as reverse DNS or PTR lookup) finds the hostname associated with an IP address. This is the opposite of a standard DNS lookup, which resolves domain names to IP addresses.
How It Works
- PTR Records - Pointer records map IPs to hostnames
- in-addr.arpa - Special domain for IPv4 reverse lookups
- ip6.arpa - Special domain for IPv6 reverse lookups
- ASN Lookup - Identifies network ownership via Cymru DNS
Common Use Cases
- Email Verification - Validate sender server identity
- Security Analysis - Identify suspicious IP origins
- Network Troubleshooting - Verify DNS configuration
- Log Analysis - Resolve IPs to readable hostnames
REST API
Integrate reverse IP lookups into your applications with our REST API. Query PTR records and ASN information programmatically.
GET Reverse IP Lookup
$
curl https://api.requestguard.com/v1/ip/reverse?ip=9.9.9.9 Response for 9.9.9.9 Live Data
{
"success": true,
"data": {
"ip": "9.9.9.9",
"version": 4,
"type": "public",
"hostname": "dns9.quad9.net",
"asn": {
"number": 19281,
"organization": "QUAD9-AS-1 - Quad9, US",
"country": "US",
"registry": "arin"
},
"queryTimeMs": 51,
"queriedAt": "2026-05-10T20:39:17.872Z"
}
}