SFTP stands for Secure FTP (File Transfer Protocol) and is a protocol that runs on top of SSH typically accessed on port 22. Because it leverages SSH as the file transfer technology, users can be authenticated against these types of servers by using a username and a password and/or a public/private key pair. Troubleshooting FTP in the command line and common errors. First time connection If this is your first time connecting to FTP through Command line on a system, you will be prompted with a firewall access verification as shown below Once you get this, click on “Allow Access”.