[CentOS] how to find unknown ip address?

Tue May 28 05:31:25 UTC 2013
Barry Brimer <lists at brimer.org>

hadi motamedi <motamedi24 at gmail.com> wrote:

>Dear All
>On my network, there is a node with unknown ip address so I do not
>know about its range and it can be any of the range xx.xx.xx.xx . Is
>there any tool on my centos server to find this unknown ip address
>(irrespective of the range of my centos server self ip range) ?

Listen with wireshark looking for things that don't belong.