Nmap

Great product. Can't beat free with a lot of front ends and some expandability.

There is a very large support community and a robust selection of add-ons and scripts. Once you get the use down this is one of the most powerful tools and you can find anything you are looking for as far as examples on the web. While not having official support its not lacking by any means.

User supported community support is outstanding. As the tool is so ubiquitous, any question you might have can be answered very quickly by one of your peers (or anyone else).

Nmap is completely free and has a vast array of configurations that it can perform. Nmap is a great tool to secure your internal and external network from most common threats. I would highly recommend it, anyone, that it's the IT infrastructure field.

NMap doesn't really have support out there. There is fantastic documentation on it located at the NMap website, but no support to speak of. In this facet, another application may be a better fit for most organizations, at least if there is a support requirement to run the application. The good news is that Nmap doesn't cost money, so if it doesn't work for you and you can't find support, you'll be no worse off than when you started.

I am not sure they have customer support, as they are a free and open source tool. But since this is a question, I would say the community does a really good job at maintaining the tool itself. New features are always added. And if you have an issue with the tool, you can always post a bug on github

The best support for it is its webpage which has more than enough information to get you going, however, there are also a million or so youtube videos, etc., so that if you are familiar with the basic ideas, you can easily get up and running with just a little work.

Its useful tool for network engineers and cyber security engineers where they used for finding the open ports.

I don't own a support with them and I have never opened any case with them. I can't give a rate on this.