Hello guys, could you pls advise?

I am complete newbie to Linux servers, have small company dealing with many freelancers, and have this need: freelancers need access to FTP server to exchange files (download work instructions, upload their work), and I only need each freelancer to see particular folders of project he or she works on. Now each of them could work on multiple projects (meaning access to more folders).

I remember long time ago I had an FTP server at home called Bulletproof, that could do something similar, but I think they only do Windows based software.

Is there a FTP server software I could ask my provider to install on the server for us that would fulfill the above requirements? Ideally one with GUI (since we're all not quite familiar with command line). The standard FTP my provider supplies with the server, cannot do what I describe above.

Thanks for any help!

Maybe consider something like NextCloud?
Would give you a few more options and ease of use than plain old ftp (and a bit more security that sending credentials in cleartext with ftp).

Welcome back.

What you describe is easy if you are familiar with system administration but overwhelming if not. We can walk you through the steps. Which distro is this for, including version?

What they are probably asking for is a secure and easy way to transfer files to and from a server. In that case you have SFTP. Basic SFTP is provided by default in the package OpenSSH-server. Ideally you want to have people authenticate using RSA or Ed25519 keys so you can turn off passwords.

With SFTP available they can use any number of graphical SFTP clients: Nautilus, Cyberduck, FileZilla, WinSCP, and more. I'd include also sshfs in that group.

(It must have been a long time ago indeed if FTP was on the table. The SSH protocol has been around since the mid-1990s and unlike FTP is encrypted. You can set up FTP if you are really, really in to retro computing but there will be no way to make FTP either safe or private. Sadly, many guides mentioning FTP that persist in remaining online, giving that long since deprecated protocol a terribly long tail. And remember that neither FTP nor FTPS are SFTP.)

Step 1: Install OpenSSH-server on your server and figure out SSH key authentication using RSA or Ed25519 keys.
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Step 2: Chart out on paper which groups should have access to which folders on the server.

Linux, and more generally Unix are multiple users OS by design, that means all you have to do is set appropriate directories permissions in the server to achieve what you want.

Hello TC, thank you for the quick reply. The current version I can see in the ISPmanager is CentOS 7.4.1708.el7.centos (x86_64), hope that is the right answer to your question. To be honest, I don't understand the rest. And the rest of the people is on very similar level as I am, so asking them to use RSA won't be very helpful. The FTP is kind of standard here, everyone is used to it, and at the moment it is what I have to stick to. Since they are freelancers, I don't have the luxury of putting them through training of using something else (they fluctuate a lot).
What I should probably mention too is that I do not have complete access to the server, it's managed server service, and I can only ask them to install software, not quite sure if your suggestion falls into that category.

Thanks for the suggestion, did not know this service before. Unfortunately, I have to stick to FTP for now, we tried another obvious solution, which was Dropbox like service, and they could not use even that. Some have even declined working with us for pushing this on them :-/

This is probably true keefaz, but I am complete noob, and have no idea how to work with that.

Yes, you should be able to do most of what you want simply by requesting installation on the server. And limiting the ability to read and write specific directories can be managed by you, if you can set file system permissions on the server. However, locking people into specific directories so they can't even see any others would require small modifications to the OpenSSH daemon's configuration.

I think it may be a matter of confusion on the names. Most of the so-called "FTP" client software these days supports SFTP out of the box. If you push forward with FTP instead, more than 20 years after it has been deprecated, you'll have a security breach on your hands eventually. FTP cannot be secured and the more users you have and the more geographically distributed they are the sooner the machine will be breached. SFTP is easier to use and is secure for the most part even if you use passwords instead of keys.

Do you have any of the clients mentioned above? If not which (S)FTP clients do you have and are familiar with?

Thanks again for trying to help!
As I said, I am quite a noob, so I only assume that SFTP is some kind of secure version of FTP, but basically the same thing. All I can tell you is that we're using clients like Double Commander to access the files on the server. I think if we can find the server solution, I can get people to use some other client. I just Googled that there are plugins for DC to support SFTP. But I need something relatively simple for that, current solution included in the system is getting really out of hand with people having to have multiple logins (one for each project) to be able to work with us.

SFTP is a completely separate protocol, but has the misfortune of having a similar name. However, all the differences are under the hood. From a user perspective, you'd be hard pressed to see differences. FTPS would be the old FTP but with SSL tacked on as an after thought. That is VERY hard to set up on the server. SFTP needs only the package OpenSSH-server installed on the server and Bob's your uncle.

About the clients, it looks like Double Commander defaults to old, insecure, deprecated FTP. I don't see any plugins that would allow secure file transfer of any kind: https://github.com/doublecmd/doublecmd/wiki/Plugins
It would be possible to use Double Commander on top of sshfs. However, sshfs would be difficult for OS X users.

Instead for OS X, I would recommend Cyberduck or, maybe, FileZilla as SFTP clients.
For legacy OS users, I would recommend WinSCP or FileZilla.
For GNU/Linux or *BSD users, I would recommend Nautilus, or their default file manager.

All of those are very, very easy to use, have graphical interfaces, and support SFTP out of the box. FileZilla, for example, allows users to have multiple login profiles in the menu.

For the client end, I'd also recommend FileZilla
(fwiw it also is avail on Linux, so you could have all your users using the same tool - easier support etc)

At the server end, openssh server as recommended.
It's usually installed on most systems for admin purposes anyway.

Hundreds of software customers needing to download updates to the software package and upload data files for server-side processing...
Several years ago, back in the stone age, we purchased NcFTPd, an ftp server that restricts users to their home directory out of the box.

I see that the license we have is no longer available for purchase, although they continue to allow its use, so it may be cost-prohibitive today. In the 20-odd years we've been running it, I'm not aware of any security breeches.

Which is NOT to say that the OP shouldn't "convert" to SFTP if at all possible. As has been pointed out, SFTP looks the same from the user interface point of view in most, if not all, clients. If users are running Windows, then I recommend WinSCP for the client software.

(Oh FileZilla is available for both Windows and Linux? As chrism01 said? Then, yes...consistent support is a great advantage)

It does not. Also, it leads to additional security problems on the server side since it requires actual user accounts.