Ethernet LAN Host Discovery Problems

# nmap -n -sP --send_ip 192.168.33.37

Starting nmap 3.83.DC13 ( http://www.insecure.org/nmap/ )
0.000 ARP Who has 192.168.33.37?  Tell 192.168.0.100
0.999 ARP Who has 192.168.33.37?  Tell 192.168.0.100
1.999 ARP Who has 192.168.33.37?  Tell 192.168.0.100
Note: Host seems down. If it is really up, but blocking our ping probes, try -P0
Nmap finished: 1 IP address (0 hosts up) scanned in 2.038 seconds