Hello
I have a friend who wants to backup files to my unraid server.

I try to find a way to do this without seting up VPN, as this makes it more complicated on my friends end, as he need to make sure the vpn is connected everytime he wants to take backup.

Yes, I know we can setup so its always connected and only the backup trafic goes through the vpn and so, but I was thinking of SFTP as an easier approtch.

 

So, my idea, since it is not a good idea to open unraid for ssh to internett, I was thinking of setting up another pc or vm as an Unraid server, setup ssh here, turn off password and only accept rsa-keys and jail the user to a folder that is mounted to an unraid share over nfs and restrict the user to only be able to use SFTP, no shell, x11 and so on.

 

I have tested this on an Unraid VM, and the jail works just fine, but my problems comes when trying to connect to the NFS share.

I know that unraid as default uses the permition nobody:users with access  777

 

For the jailing to work, the owner needs to be root and the access should be 755 on the jail-root folder.

 

If I try to change the owner and permition for an unraid share, it does not stick, afrer some time, its back to nobody:users with access  777, is this normal? (I know, I should know this by now)

 

I have also tried, from the ssh server side, after mounting the share, make an folder inside and change the owner of it to root and setting the permitons to 755 and use this as the jailroot in the sshd_config file on the Ubuntu (ssh) server. It seems to stick and not geting changed back after some time.

 

So, is this an safe way to do it or should I just keep to OpenVPN and teach my friend how to use it?

 

No matter what, this was very fun to explore and get to work

 

 

 

 

 

 

Have a look at Tonido, it offers a local cloud service without the need to open up your router/firewall. This allows for sharing without sacrificing security.