$ ping 1249739877 PING 1249739877 (74.125.132.101) 56(84) bytes of data. 64 bytes from 74.125.132.101: icmp_req=1 ttl=41 time=395 ms ...
$ nslookup 74.125.132.101 Server: 127.0.0.1 Address: 127.0.0.1#53 Non-authoritative answer: 101.132.125.74.in-addr.arpa name = wb-in-f101.1e100.net. ...