# Reverse DNS lookup. { dig -x 216.92.34.251; dig -x 209.197.123.153 ; } | awk '!/^;;/ && /perlmonks/' 251.34.92.216.in-addr.arpa. 7122 IN PTR perlmonks.org. 153.123.197.209.in-addr.arpa. 7192 IN PTR perlmonks.pair.com.