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Possible Duplicate:
How to find unused IP Address on a network?

currently I am using nmap wich scans the range of IPs that my DHCP server assigns to hosts. However this is a) slow and b) sometimes nmaps doesn't discover all hosts. Laptops that are connected wirelessly sometimes aren't counted.

I tried almost all possible nmap scan techniques like:

sP,sS, sT, sW, sM etc... they all miss out the laptops sometimes although I can ping them at any time.

I am looking for an efficient way to accomplish this without missing out some hosts. My Router is a Linksys WRT54GL and I am using the latest Tomato firmware.

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imbaer
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1 Answers1

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You can also try arp-scan (install using sudo apt-get install arp-scan on a terminal)

It returns MAC addresses and tries to find the manufacturer of the network adapter.

ie, sudo arp-scan --retry=8 --ignoredups -I eth0 192.168.1.0/24 (--ignoredumps and --retry=8 make the results more accurate) returns

Interface: eth0, datalink type: EN10MB (Ethernet)
Starting arp-scan 1.8.1 with 256 hosts (http://www.nta-monitor.com/tools/arp-scan/)
192.168.1.1 68:7f:74:a5:07:18   Cisco-Linksys, LLC
192.168.1.5 00:11:32:07:71:ac   Synology Incorporated
192.168.1.100   00:21:9b:f8:ec:1c   Dell Inc
192.168.1.117   00:12:fb:1a:88:8a   Samsung Electronics

4 packets received by filter, 0 packets dropped by kernel
Ending arp-scan 1.8.1: 256 hosts scanned in 1.377 seconds (185.91 hosts/sec). 4 responded

Give it a try.

Bruno Pereira
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