Stands for "File Transfer Protocol." FTP is a protocol designed for transferring files over the Internet. Files stored on an FTP server can be accessed using an FTP client, such as a web browser, FTP software program, or a command line interface.
An FTP server can be configured to enable different types of access. For example, an "anonymous FTP" configuration allows anyone to connect to the server. However, anonymous users may only be allowed to view certain directories and may not be able to upload files. If anonymous FTP access is disabled, users are required to log in in order to view and download files.
The standard FTP protocol is not encrypted, meaning it is vulnerable to packet sniffers and other types of snooping attacks. Therefore, the FTPS and SFTP protocols were developed to provide secure FTP connections. FTPS (FTP with SSL security) provides SSL encryption for all FTP communication. SFTP (SSH File Transfer Protocol) is a secure version of FTP that uses SSH to encrypt all data transfers.
FTP not commonly used on phones, although there is FTP software available for most smartphone platforms.