A colleague and I recently struggled with her review of a somewhat flawed managed network switch. After hours of troubleshooting, we were unable to determine the IP address of the switch despite the fact that it was connected to our network. I’d usually use a network mapping tool on my laptop to query all of the devices on the network and, hopefully, see every device’s IP address. If I’d had the Network Discovery app installed on my Android smartphone, it would have been a much more portable solution.
Network Discovery will not only perform a discovery of devices on your network, but it’s also a port scanner. This little app is free and incredibly handy, besides an occasional crash or two.
Install and Network Discovery
I installed Network Discovery version 0.3.5 from Google Play. The app is supported on Android 1.5 and higher and is a download size of 256k.
Once I opened the app, it asked if I wanted to download the NIC database, a database of vendors’ network interfaces that lets the app ID scanned devices correctly. I hit yes, and after a scant second, the download was done (it’s a sub-500k download). Immediately after that the screen showed the wireless network to which my phone was connected. It displayed the IP address range, SSID, and connectivity mode (which, with my phone, was Wi-Fi).
There are two buttons at the top of the home screen: Discover and Options. I tapped Discover and network discovery commenced. The app correctly identified the two devices I have on my network (besides the Android phone), my laptop and my router.
The IP address, MAC address, and vendor name are displayed for each discovered device. Interestingly, my laptop is a Dell but the app displayed the vendor as Hon Hai Precision Ind. Co., Ltd.—the component manufacturer more commonly known as Foxconn. Foxconn makes the motherboard in my Dell. Not exactly incorrect, but somewhat confusing. My router was correctly ID’d as Netgear.
Network Discovery is also a port scanner. The app showed that on my laptop ports 135, 139, 445, and 554 were opened.
Scanning with Network Discovery was much faster than with the free port scanner I usually use on my laptop. But the laptop app does not show open ports, whereas Network Mapper did. I’m confident that Network Mapper got the ports right, because I opened them myself!
Tapping on the Options button brings up some settings you can change. You can specify, for example, the network interface for the device from which you are performing a scan. Since this is an Android app, you will likely run it while connected wirelessly from your device. If so, the app uses the interface for a wireless adapter automatically. Wireless adapter interfaces are designated in networking shorthand as “wlan0.” You can also specify other interfaces, such as rmnet for cellular, USB, p2p, and ip6tnl.
You can opt to show service banners from connected sockets. This means if you do a scan and the app detects an SSH port open, the app will show the port number and label it “SSH.” Displaying banners can conceivably slow down scanning, so if you are scan a network with a lot of nodes, having the choice to disable is handy.
Users can also choose to resolve the hostname of discovered devices to their IP addresses. You can have the app vibrate your Android device when the scan is complete; good if you need to put your device down. A NIC database update can be manually initiated.
Other customization options include switching the network device discovery method from Ping (which is default) to a DNS request. The can perform mobile discovery also. Advanced users can specify the number of threads to use in a host discovery (1-256). Additionally, you can set the first and last ports to scan as well as the connection timeout interval.
Finally, there’s a Wi-Fi setting which take you back to the home screen to see the wireless network you are connected. Every time I tapped it though, the app crashed.
Definitely Worth a Beer
What I really like about this little app is that it’s got an export feature. You can save your scanned device list as an .xml file. Network Discovery is light on in-app help, such as clearer definition of terms, but it is free. The developer provides a link to the company’s website, as well as a Pay Pal donation button with the note next to it inviting you to help him buy a beer if you like the app.
Despite the crashing and the lack of help or a knowledgebase on the company website, this app is still a solid three and half out of five stars for Android networking utilities. Network Discovery is a neat little tool, and one I will leave on my phone even after I finish the review. The next time I’ve got a device on my network that seems unwilling to give up its IP address, I’ll have Network Discovery ready to go.
Copyright © 2012 Ziff Davis, Inc