I didn’t go into much detail about the apps in that post since it was
focused on catching unauthorized users on your network. In this
article, I’ll talk in more detail about these two apps that can be used
on Apple or Android devices and I’ll also mention desktop apps that you
can run on Windows and Mac OS X.
These network scanning tools allow you to not only see all the
devices on your network and their IP addresses, but also view folders
shares, open TCP/UDP ports, hardware MAC addresses and more. So why
would you care about this information?
Though it’s a bit technical, the information can help you make your
network more secure. For example, you may find folders that are being
shared on your network by accident. Anyone who connects to your network
via cable or wireless could then easily search for shared folders and
copy that data to their computer.
When looking at open ports for a computer or device, you can easily
see whether remote desktop is enabled, whether an FTP or HTTP server is
running and whether file sharing is enabled or not. If you never connect
to your computer remotely, then having
remote desktop enabled is just a security risk.
Windows Network Scanner
Let’s start off with a free tool for Windows PCs called
SoftPerfect Network Scanner.
I like this tool because it’s updated often, runs on Windows 10 and has
a 32-bit and 64-bit version. The program also doesn’t require any
installation, which means you can carry it on a USB stick or save it to
Dropbox and use it on any computer you want.
When you run the executable file for your version of Windows (
determine if you have 32-bit or 64-bit Windows), you might see a message saying that Windows Firewall has blocked the program. Make sure
Private networks is checked and then click on
Allow access.
Once the program loads, you’ll need to enter your network starting
and ending IP address range. If you don’t know this, don’t worry. Just
click on
Options,
IP Address and then click on
Auto Detect Local IP Range.
You’ll get a popup window with the detected IP addresses for IPv4 and
IPv6 on any network cards you have installed, including virtual ones.
For most home users, you’re only going to see one item listed under both
IPv4 and IPv6. Unless you have IPv6 setup, you should click on the
network card listed under IPv4.
Now you’ll be brought to the main interface again, but now the IP address range will be filled in. You’ll see the
Start Scanning button at the right, which you can click to start a scan.
However, you should first set the scanning options before performing a scan. Click on
Options and then
Program Options. On the
General tab, the only option you may want to check is
Always analyze device.
By default, the scanning program will only show you devices that
respond to certain requests, so the final list may not show all the
devices that are actually on your network because some devices simply do
not respond.
The scan does take quite a bit longer (several minutes compared to
several seconds), but it’s worth it if you really want to see every
device on your network. The
Additional and
Workstation
tabs are really only useful for corporate environments where you have
many machines on the same network and you want to get information about
each computer. The
Ports tab is where we can to go next.
Check the
Check for open TCP ports box and then
click on the little paper icon at the far right of the text box. This
will open another window that lists out some TCP port groups. You want
to click on
HTTP and Proxy and then press the
SHIFT key and click on
Database servers to select all three items.
Back on the main screen, you should see all the port numbers listed in the text box. Go ahead and also check all the boxes for
open UDP ports.
At this point, click OK to go back to the main program screen. Now
click Start Scanning and you should see results slowly added to the
list.
In my tests, the program was able to find 16 devices on the network when checking the
Always analyze device
option compared to just 11 items when not checked. Any item with a plus
sign to the left of the IP address means that it has shared folders.
You can click on the + sign to see the shared folders.
The
Host Name column should give you an easy to understand name for the device. On the right, you’ll see a column called
TCP Ports,
which will list out all the open ports for that device. Obviously, the
numbers don’t make much sense unless you know what they means, so check
out this
Wikipedia page that describes each port number in detail.
If anything has port
80 (HTTP) listed, that usually
means it has some kind of web interface and you can try connecting to it
via your browser by simply typing in the IP address. Port
443 is for secure HTTP (HTTPS), which means you can connect to it securely also.
Mac Network Scanner
On the Mac, you have a couple of options.
LanScan
is a free app on the Mac Store that does a very simple scan and
displays the IP address, MAC address, Hostname and Vendor. The free
version will only list the first four hostnames fully and the rest will
only show the first three characters. A little annoying, but probably
not a huge deal on most home networks.
You’ll also notice that it only found 12 items and that’s because it
doesn’t have any options to scan each IP address regardless of whether
it responds or not. A better network scanner for the Mac is
Angry IP Scanner shown below. It’s open source and works on Windows, Mac and Linux.
By default, the program also scans open ports, which LanScan does not
do. The only issue with this program is that you have to have Java
installed in order to run the program. Java is a big security risk and
is disabled on most Macs by default, so you would have to enable it
manually.
Smartphone Apps
I have two apps that I use, both of which are free, and one that can
you download on Apple devices or Android devices. Both apps are
excellent and pretty much give you the same info, but each has its
pluses and minuses.
Fing is a free app that is available on the
Google Play store and the
iTunes store and
has a great looking interface. You don’t have to worry about entering
any IP address range with these apps because they figure it out on their
own. Once you start a scan with Fing, you’ll get a nice looking list of
devices with some basic info like hostname, MAC address, IP address
etc.
If you tap on a device, you’ll get another screen where you can give
the device a custom name (a feature I really like), enter a location and
even add additional notes. If you scroll down, you’ll see an option
called
Services, which lets you see scan the device for open ports.
The only downside I have seen with this app is that it doesn’t list
out all the devices on the network. It only caught about 12 devices on
my network out of the 16 that the Windows program had found.
The second app I like using is
Net Analyzer,
available from the App Store for free. You run a scan by tapping the
Scan button at the top right and you’ll get a list of all your devices
within a few seconds.
Using this app, I got 15 devices, which was pretty close to the total
number of devices on the network. With Net Analyzer, you’ll also see
some colored letters on devices that have certain services enabled. The
green
P means it is pingable, the brown
B means Bonjour services are available (Apple devices), the red
G means it’s a gateway device (router, etc), and a blue
U means UPNP and DLNA services are available.
You can tap on a device to get more information and perform queries
on the device. Tap the Query with Tools option shown below once you tap
on a particular device.
On the next screen, you’ll see several options including
Ping, Route,
Ports,
Whois and
DNS. Tap on Ports, choose
Common or
All and then tap Start at the top.
As the scan progresses, you’ll see the ports that are open and active
and also which ports are blocked. The app also has other tools that you
can use to scan specific devices on the network to get more
information.
Hopefully, these tools will allow you to fully see what devices are
on your network and what services and ports are open.