Managed file transfer (MFT) applications should be protocol agnostic, meaning a business can exchange a variety of files, internally or externally, regardless of transfer protocol, file type or size. The most common protocols for transferring files are FTP, FTP over SSL/TLS (FTPS), FTP over SSH (SFTP) and HTTPS. AS2 is also commonly used, but it is typically only needed for electronic data interchange (EDI), which is a specific use case sometimes referred to as B2B communication. (If you are interested in EDI, this guide is not for you.)
Here is a table of the most common protocols with pros and cons.
File Transfer ProtocolNetwork Protocol TypeDefault Network PortEncryptionUse CaseProsCons HTTPTCP80No encryptionSending files from a web server.NoneNot secure and not recommended. HTTPSTCP443EncryptionSending files from a web server.Firewall friendly. Port 443 is normally always open for outbound connections so this file transfer protocol can be easier to manage as it does not require client software. Authentication does not require certificates and can be done. FTPTCPNo encryptionSending/pushing from an FTP client installed on a computer or receiving/pulling files from a FTP server to the FTP client.NoneNot secure and not recommended. It's unencrypted and is not designed for today's more advanced security standards or compliance requirements SFTPTCP22Secure Shell (SSH) provides a secure data stream and encrypts the authentication credentials and the actual files being transferred. SSH prevents hackers from intercepting the files in transit.Probably the most common protocol for automated file transfer but does require some administration. The IT team will need to manage public/private keys for all the SFTP clients.It is more difficult to set up an SFTP client and manage keys. SFTP is slightly slower than FTPS because SFTP uses the same channel for control and data. FTPSTCP21/990FTP connections are established from the client to the server via Explicit or Implicit control channels. Explicit FTPS control connections take place on TCP port 21. Implicit FTPS control connections take place on TCP port 990.Requires authentication using public and private keys which is part of the public key infrastructure (PKI).