On 6 Aug 2023 20:01 +0800, from jon@daydaylive.us (Jon Smart): > but can an IP have multi hostnames in PTR? Sure. It's perfectly allowed. PTR is just another RRtype, and there's nothing particularly magical about the in-addr.arpa zone. But actually doing it is generally a bad idea in practice. -- Michael Kjörling 🔗 https://michael.kjorling.se “Remember when, on the Internet, nobody cared that you were a dog?”