This works for me on Centos 5.6. It may assist newcomers to the Linux world of Centos. whois 51.51.51.51 produces a normal and conventional display of data. However since ARIN, the North American registrar of IP addresses, "modernised" its WHOIS processing, a query to whois 64.64.64.64 will produce a one line summary of possible matches, which always includes ARIN, but omits the details we used to receive before ARIN implemented its much criticised "improved" service. A one line script solves it for me (but only for ARIN network entries). #!/bin/bash whois -h whois.arin.net n + $1 I call my script .arin .arin 64.64.64.64 produces a normal output. Paul.