Automatic backup not to FTP

Like @kcheng already said there is no built-in support in Fortigate for such back up destinations. But for the benefit of other readers of this post, I will go and add that none of the back up destinations seem safe enough, or according to the best practices of today. 

• Cloud storage? It is a matter of time until someone by mistake makes this S3 bucket public-read, and ongoing scans discover it.
• Shared folder/SMB? The first place any malware/ransomware will look for once inside the network.
• Email? Makes it so much easier for someone by mistake/maliciously to forward the configs, or leave it in the forgotten external harddisk/storage backup of the mail server. Also, one of the favored by malware/ransomware agents to get hands on/dump mail server backups/storage.

Yes, Fortigate encrypts all passwords/PSKs in the config when exported, but still, having the complete firewall config file available makes malicious actors' life so much easier.

The usual practice in the corporate/Ent environment is either to have a dedicated product that backs up config securely, or set up custom hardened server (SFTP/SCP) with encrypted filesystem and with very restricted access controls to it. 

Thanks Yuri and Kcheng!

I prefer to have an unsecure backup outside the fortigate than do not have any backup or an old backup.

I will try with scp, although I think I will need to install a program because we have few PCs with linux

Anyway, is good to know the options.

Regards!

Damián