Open your NAS settings and you're offered SMB, AFP and NFS, sometimes all switched on, with no hint about which one you should actually use. You just want your computer to see the files. The good news is that for almost everyone the answer is simple, and the other options only matter in specific cases.
What each protocol is for
SMB is the universal one. It's built into Windows, macOS and Linux, so a single protocol lets every machine in the house reach the NAS. AFP is Apple's older file-sharing protocol, designed back when Macs needed their own path to a server. NFS comes from the Unix world and is common on Linux, where it's valued for performance and its permission model.
Why SMB is the default worth choosing
For a normal mix of computers, SMB is the one to turn on and leave on. It works everywhere without extra software, it handles the file names and characters people actually use, and it's the protocol NAS makers themselves treat as standard. There's rarely a reason to complicate things beyond it.
Where AFP and NFS still fit
AFP is fading. Apple has used SMB as the default on macOS for years and has deprecated AFP, so on a current Mac there's no benefit to it and some risk of quirks. Keep it only if an old device genuinely needs it. NFS earns its place in Unix and Linux setups, and for things like hosting virtual machine storage, where its speed and permissions are a good match. For a household of Windows and Mac machines, it's more configuration than it repays.
What this means for your tools
Because SMB is the common tongue, an app that speaks it fits anywhere: any of the three operating systems, any brand of NAS. That's the approach NAS Ranger takes, which is part of why it's built the way it is. It connects over SMB, so the same app cleans a Synology from a Mac or a QNAP from a Windows PC without changing anything.
Try it free: connect over SMB from whatever computer you have and scan your NAS for duplicates, no protocol juggling required.