Frequently Answered Questions

Here we have the FAQ for the Fl0wer platform product.

Evaluation version limitations

The evaluation version has the following limitations:

  1. Multi-threading is disabled. You will have only 1 thread processing incoming data.
  2. Can only store Netflow data in binary file format "demo" which is 16K per flow and stores only the minimal netflow Information (after all, it's for evaluation purposes, not for real production !). Since version 1.3 it can also store data in CSVFULL data format so you can evaluate the integration with your favorite Analytics (ELK, Splunk, etc.) .
  3. Does not handle Netflow V9 and IPFIX.
  4. Does not handle IPv6 Flows.
  5. Allows only Dynamic SSLv23 In-Memory Certificates (regenerated after each daemon restart)

Apart from this, it has no time limits, no limits on the number of flow exporters or anything else.

Licensing questions

To work properly, the licensed version requires a binary encrypted license file that states who the RTU (Right To Use) is assigned. This license file is provided via mail in the form of a password protected zip file to customers that purchased the product within 24/48h from the purchase date. If for any reason, you did not received it, please get in touch with me providing me the order number and the activation key that was sent you when you placed the order. The activation key is totally unrelated to the contents of the license file, so please, don't lose your time trying to use it. The activation key is the password for the encrypted zip file. The license file is required only on the server platform, the clients don't need it, so you can use them with the evaluation version.

Fl0wer by itself has no copy protection mechanism, apart the license file. As a long experienced system administrator, what I understood is that any kind of copy protection generally creates limits for customers and, in a way or another, if a person is determined to bypass it, he'll manage to do it. This is not the user experience that I want for my customers, for which I want the best. But I expect my customers to keep safely the license file since it contains their data.

Important: no refunds will be provided once the license file is sent to the customer.

Product questions

Windows & Linux clients ... but Linux ?

It's obviously included in the package distribution :-)

Why didn't you use Web Technologies and are you using a Client-Server model ?

First, Web Technologies are a Client-Server model (you simply use always the same client :-) ), second, simply because using Web Technology provides unneeded overhead, third Web Technologies have an average life curve of 6/12 months then change, fourth nobody stops you to develop a frontend using Django, Flask or whatever stuff is trendy now. I wanted to build a solid and expandable product, not a fashionable one.

Do I need to purchase a Signed Certificate to use with the JSON API ?

It always depends on what you are trying to achieve in your use case, but in normal usage I would say no, you don't need. Currently no checks are done on the certificate in the source code (you can see by yourself), although nothing prevents you to set them up writing appropriate code, but for general usage it would probably be an overkill.

Remove the evaluation package before installing the licensed version

If you evaluated the DEMO version and decided to buy the licensed version, save your configuration file and data, remove the demonstration package with your Linux distribution commands (dpkg or rpm) and install the licensed version. Binaries are different and the evaluation version simply doesn't contain all the features in the full featured version. It's a simple job even for a junior Linux system administrator, they are described in the user manual.

Is it a multi-tenant solution ?

Fl0wer has no idea of who are the Flow Exporters since they are learned dynamically, so it cannot split the traffic by customer. If you want to split traffic by customer you should use different instances on the same or different hardware, making your sizing considerations. Discounts for quantities can be discussed.

Does Fl0wer support sFlow ?

Yes. sFlow v5 flows are now supported, altough sFlow is a sampled protocol.

Does Fl0wer support UDP packet replication for other collectors ?

No, but it is not really needed. You can simply use Samplicator ( to do this. Simple, clean, working, straightforward. I use it, for example, to send all Netflow data to all my active collectors for development & testing.

My device does not support Netflow or How can I get data from a Switch ?

If your device supports port-mirroring (also called port-span) then setup a Linux system with an interface receiving traffic from a mirrored port (replicating the one with the interesting traffic) and have it processed by softflowd ( or sending data to Fl0wer. If you are going to mirror a switch-port with 802.1Q Tagged VLAN traffic, use the version with the vlan patch (

My licensed Fl0wer collector is using only 1 core

If you are running Debian 7 (or one of its derivates) with the stock 3.2 kernel this is expected, since the SO_REUSEPORT system call is available in 3.9+ Linux Kernel Versions and Debian 7 is 3.2.0. RHEL 6 and CentOS 6 should work smoothly since this feature has been backported to 2.6.32 in these distributions. Anyway, if you are running this Linux Distribution and don't want to update it to a most recent version, you can update the kernel. Here is a nice procedure to do a kernel upgrade for Debian 7 using the backports as example. If you have only 1 CPU core, that's the most that Fl0wer will do (indipendently on the Kernel version). If not, please contact me at [email protected]


There are free Netflow collectors, why should I pay for your product ?

Well, if you're here, it probably means you're not extremely satisfied with the free alternatives, as I was. Its cost is very reasonable, even for a very small company, and it covers the time you spend (or the money you spend for a professional) setting up a properly configured free alternative, do your math. Also, it allows you to create highly customizable solutions and integrations. And supporting the product buying a RTU for a licensed version, you support the developer (me, I'm a one-man band) and you help product improvement.

Partners & Resellers

If you want to became an authorized Fl0wer partner or reseller, use the Contact form and get in touch !


Free, limited, support is provided to the licensed users for 1 year from the purchase of the RTU.

Free limited support entitles the user to:

  • ask for questions
  • report bugs that, if confirmed, will be fixed in the next release
  • suggest improvements

Anyway, does not entitle the user to ask for customized bugfix releases.

Professional paid support or consultancy can be purchased on the store using PayPal as the payment method (it is a policy, the eCommerce platform that hosts Fl0wer). Full working licenses and remote services can be purchased directly from the author contacting [email protected] .