Check Reverse DNS

To check if ptr record is set aka reverse dns:

$ ping -c 2 example.com
PING example.com (93.184.216.119) 56(84) bytes of data.
64 bytes from 93.184.216.119: icmp_seq=1 ttl=53 time=228 ms
64 bytes from 93.184.216.119: icmp_seq=2 ttl=53 time=228 ms

Get IP:

$ host 93.184.216.119
Host 119.216.184.93.in-addr.arpa. not found: 3(NXDOMAIN)

This example is the ip for example.com which does not have a PTR/Reverse DNS Record