Unlike port scanners, which scan for open ports, IP scanners simply try to find hosts that are alive on a network. If you are searching for IP scanners for Windows, you will surely find an abundant supply of them. In Linux, however, you may be searching a little harder to find a quality, easy to use IP scanner. Here is a list of the 3 best IP scanners for Linux, rated on speed and usability.

1. arp-scan - Arp-scan is an easy-to-use tool that can find alive hosts on a network. It sends ARP packets to specified hosts and displays any responses. I rated arp-scan #1 because of its simplicity and speed. By simply adding the -l switch to arp-scan, it will automatically determine the network settings and scan the network of the first adapter. It also scanned the network the fastest. To install arp-scan:

Ubuntu: sudo apt-get install arp-scan

OpenSuse (12.1): wget http://download.opensuse.org/repositories/security/openSUSE_12.1/i586/arp-scan-1.8-1.1.i586.rpm

sudo rmp -i arp-scan-1.8-1.1.i586.rpm

The easiest way to scan the network you are in is to run any of the following commands (they all do the same thing):

sudo arp-scan -l    #Scans the local network

sudo arp-scan 192.168.1.0/24     #Scans 192.168.1.0 255.255.255.0

sudo arp-scan 192.168.1.1-192.168.1.254     #Scans the obvious range

You will see results like this:

192.168.1.10 00:0c:29:a4:16:48 VMware, Inc.

192.168.1.11 00:0e:2e:3a:c1:2d Edimax Technology Co., Ltd.

192.168.1.20 00:e0:81:31:97:47 TYAN COMPUTER CORP.

Total Time: 1.381 seconds

2. nmap – Nmap, better known for its port scanning abilities, is also quite suitable as an IP scanner. I rated nmap #2 because it returned the results slighty slower than arp-scan, and there is no -l switch to automatically determine the network settings, as with arp-scan. To install:

Ubuntu: sudo apt-get install nmap

OpenSuse: sudo zypper install nmap

To scan for alive hosts on a network, run any of the following commands (they all do the same thing):

sudo nmap -sP 192.168.1.0/24     #Scans 192.168.1.0 255.255.255.0

sudo nmap -sP 192.168.1.1-254     #Scans the obvious range

You will see results like this:

Host 192.168.1.11 is up (0.0089s latency).

MAC Address: 00:0E:2E:3A:C1:2D (Edimax Technology Co.)

Host 192.168.1.20 is up (0.00063s latency).

MAC Address: 00:E0:81:31:97:47 (Tyan Computer)

Host 192.168.1.21 is up (0.00099s latency).

MAC Address: 00:E0:81:31:45:26 (Tyan Computer)

Total Time: 1.82 seconds

3. Angry IP Scanner – This tool, perhaps better know to Windows users, is also available on Linux, as a Java application. I rated Angry IP Scanner #3 because it is significantly slower than arp-scan and nmap, however, it has a nice and simple GUI that many people find intuitive. To check if you have Java installed, run this command:

java -version

To install Java, run this command:

Ubuntu : sudo apt-get install openjdk-6-jre

OpenSuse: sudo zypper install java-1_6_0-openjdk

You can download the Angry IP Scanner here:

http://www.angryip.org/w/Download

Ubuntu: wget http://sourceforge.net/projects/ipscan/files/ipscan3-binary/3.0-beta6/ipscan_3.0-beta6_i386.deb

sudo dpkg -i ipscan_3.0-beta6_i386.deb

OpenSuse: wget http://sourceforge.net/projects/ipscan/files/ipscan3-binary/3.0-beta6/ipscan-3.0_beta6-2.i386.rpm

sudo rpm -i ./ipscan-3.0_beta6-2.i386.rpm

There are 32 and 64 bit Deb and RPM files for Debian/Ubuntu and Fedora/RedHat/Suse/Mandriva. Angry IP Scanner is one of the few IP scanners for Linux that has a nice GUI. It's very simple to use. Simply enter the range of IP addresses you want to scan and click Start:

Total Time: 25.9 seconds

As you can see, there are several high quality and fast IP scanners for Linux. If you have a favorite that isn't listed here, feel free to leave a comment.