[gluck@root ~]$ nmap 10.0.0.0/24 -sP

Starting Nmap 5.51 ( http://nmap.org ) at 2012-10-18 09:19 MSK
Nmap scan report for root.dotty.su (10.0.0.1)
Host is up (0.0011s latency).
Nmap scan report for 10.0.0.5
Host is up (0.00063s latency).
Nmap scan report for dc2.dotty.su (10.0.0.6)
Host is up (0.00051s latency).
Nmap scan report for 10.0.0.40
Host is up (0.00036s latency).
Nmap scan report for notebook.dotty.su (10.0.0.101)
Host is up (0.0081s latency).
Nmap scan report for 10.0.0.111
Host is up (0.0071s latency).
Nmap done: 256 IP addresses (6 hosts up) scanned in 2.25 seconds

[gluck@root ~]$ host 10.0.0.40
40.0.0.10.in-addr.arpa domain name pointer mail.dotty.su.

[gluck@root ~]$ host 10.0.0.5
5.0.0.10.in-addr.arpa domain name pointer dc1.dotty.su.

[gluck@root ~]$ host  10.0.0.111
111.0.0.10.in-addr.arpa domain name pointer nettop.dotty.su.

[gluck@root ~]$ cat /etc/resolv.conf
; generated by /sbin/dhclient-script
nameserver 127.0.0.1
nameserver 192.168.2.90
search fryazino.net