UPDATE JULY 2020: It would appear as the FreeBSD Package website has gone down, and has been for several weeks. This guide will not work as of July 2020.
ntopng is software that can monitor network traffic and is essentially Deep Packet Inspection. ntopng is available on pfSense’s package manager which allows for easy installation. However, this package isn’t always updated. Specifically, on May 9, 2020, that latest version of ntopng is version 4.0, but the pfSense package is still on 3.8, a version released two years ago. Since pfSense is based off of FreeBSD, ntopng can be manually overridden with the latest version on the FreeBSD repository.
To start off, install the ntopng package on pfSense, located at System>Package Manager>Available Packages. If you already have it installed you can skip this step.
Grabbing the Latest ntopng Package
The latest compiled build of ntopng for FreeBSD can be found at https://pkg.freebsd.org. To find the package you must first know the version of FreeBSD your pfSense software is on. This can be done by going to the System Information widget on the pfSense Dashboard under the Version section.
As you can see above, my system is currently on FreeBSD 11.3 amd64.
Now that your system version is determined, head back to the FreeBSD packages page. Select your FreeBSD version, latest, All. For example, my version is located at https://pkg.freebsd.org/FreeBSD:11:amd64/latest/All/. Now you need to find the ntopng link within here, and can be done by using the “Find” function on your browser and searching for ntopng.
You will also need to grab the latest ndpi link. It can be found the same way as finding the ntopng package.
SSHing Into pfSense
After the latest ntopng link is grabbed, we need to gain console access into pfSense. This can be done via physical access, or over SSH. If you are SSHing, make sure SSH is enabled in System>Advanced. Upon successful completion, you should receive a screen similar to below.
Press 8 to enter the console.
Now that you are in a console, enter the following command.
pkg add -f ntopng-link-here
Substitute ntopng-link-here with the link you copied from the FreeBSD package website. It will look similar to the code below.
pkg add -f https://pkg.freebsd.org/FreeBSD:11:amd64/latest/All/ntopng-4.0.d20200414,1.txz
This command will overwrite the existing pfSense package, upgrading it. A successful message will appear, similar to the one below.
Next, we have to install the latest ndpi package. It will look similar to the code below.
pkg add -f http://pkg.freebsd.org/FreeBSD:11:amd64/latest/All/ndpi-3.2.d20200403_1,1.txz
Now you should be able to navigate to the pfSense GUI and configure the latest version of ntopng to your heart’s content. If ntopng does not start, try restarting the service and/or restart pfSense.