Microsoft offers software licenses through a program called the Service Provider License Agreement. The SPLA model provides use of Microsoft products through a monthly user or processor based fee. SPLA software includes the Windows Operating System, Microsoft SQL Server, Microsoft Exchange Server, Microsoft SharePoint and shoutcast hosting, and many other server based products.
What are your plans for the server? Do you want to set up a blog to post about your life or build an info page for a charitable cause or NGO? It is unlikely that these ventures will place excessive demands on the CPU (processor) and RAM (working memory), and thus hard drive storage should certainly be enough. The same applies to smaller online games and to installing a TS3 (Teamspeak 3) server as a communication platform. A vServer will be perfectly sufficient for these projects. What’s more, the IONOS VPS grants you root access, giving you a lot of freedom.
The answer to this question largely depends on two factors. Are you new to server technology and not very interested? In this case, Windows is the easiest option to get where you want to go. Do you already have experience with Linux or would you like to familiarize yourself with this operating system? If so, Linux gives you more freedoms to configure your server, and you will be using an operating system that is less vulnerable to attacks from the Internet. Linux is also open source and therefore free.