Samba or another?

After using OpenSUSE for many years, it’s time to immerse myself and fine-tune the operating system in my Linux computers.
I have a mix of OpenSUSE and Windows computers in my network, all behind a firewall (Sophus UTM) that uses VPN (through an ASUS router) to access the Internet.

My question is:
What kind of network protocol should I use between my OpenSUSE 42.3 computers to move files quickly and safely? How do I configure this protocol?
I’m using Samba right now but it’s only because I have Windows computers on the network, so I have to continue using it?

How do I do, all configuration tips and referrals are needed and appreciated?

/ Roland

I think there is no general “best” solution. Depending on need you could use NFS (well, NFS is not realy a file transfer tool, but from a mounted remote file system you can of course “transfer” with local copy tools), rsync, ftp and maybe more.

(I omit Samba, because that is an interface with Microsoft operating systems when I understand you correct, this is about Unix/Linux systems only).

If I’m doing a direct machine to machine impromptu file transfer, scp and winscp can be used without setting up server services and network shares. Midnight Commander is a popular graphical app that supports a number of ways you can view and transfer files to/from a remote machine.

If you want to set up something more permanent and can be browsed, then some kind of network services can be set up.
SAMBA is good for file discovery and transfers within your LAN.
For both LAN and if you want to provide Internet access to your files, you’d need to configure something based in Internet protocols like FTP/SFTP/FTPS or HTTP/HTTPS.
If you want to transfer massively large files, torrent apps will transfer files in the most reliable way (or use specialized apps like Filezilla that do automatic file and chunk verification).
Or, within your LAN, you can also set up a distributed block storage system like iSCSI.
If you want a similar block storage system that supports site to site as well as within your LAN, you can consider something like CEPH.

So, lots of options to fit a variety of needs.