A simple DNS lookup tool
Domain 27.51.76.50
Type PTR
Server Cloudflare
Duration 675 ms
Results
JSON ZONE 
{
  "status": "NOERROR",
  "from": "1.1.1.1",
  "answer": [
    {
      "type": "PTR",
      "name": "27-51-76-50.adsl.fetnet.net",
      "ttl": 3600
    }
  ]
}
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