Whenever you download your backup files you can fall prey to a malicious user. Backup files are transferred unencrypted (unless you access your site's administrator section through the HTTPS protocol). It is possible for a resourceful hacker to launch a man-in-the-middle attack. In such a case, whatever you download from your site will be directed to the hacker's computer before reaching yours.
To avoid such insecure scenarios, we advise against using thebutton in the backup administration page. We suggest that you use Secure FTP (SFTP) instead. Avoid using the plain old FTP, because your password and data are transmitted in clear text (unencrypted) over the Internet. Also avoid FTPS and FTPES (FTP over SSL) as they have some security restrictions, like requiring your FTP server to have a commercially obtained SSL certificate in order to be really effective. Sometimes, your host will allow secure access to a web based control panel which has a file download feature. You could use this, it's as safe as it gets.
There is also another reason why not to use the Joomla!™ back end, the data transferred counts towards your monthly bandwidth quota. Backup archives are large, sometimes in the hundreds of megabytes. Transferring them through the Download feature will incur a huge loss on your monthly bandwidth quota. Using Secure FTP or your host's control panel usually does not count through the bandwidth quota and should be used instead. It's better to ask your host, though; some include the FTP and SFTP traffic in your monthly bandwidth quota. Finally, the Download feature doesn't work with all possible configurations and has objective problems with the handling of very large archives; this is a technical limitation which can not be overcome in the PHP level the component operates. Most notably, many servers which use the FastCGI mode do not work at all with the button. They will simply throw an HTTP 500 error page, or a "file not found" message. We've tried all the tricks in the book and then some more, but there's really absolutely nothing we can do about it. Sorry.button in the backup administration page. Your host neither discriminates the back end and front end pages of your Joomla! site, nor your IP from the rest of the world. As a result, every time you use the
The preferred and suggested method for downloading your backup files - for several reasons - is using FTP in BINARY mode, preferably over an encrypted connection. Alternatively, you can use Remote CLI which allows you to use this approach when downloading backup archives.