Dictionary · Protocols and Ports
FTP
FTP — File Transfer Protocol
File transfer · Beginner
A file-transfer protocol that uses a control connection on port 21 and a separate data connection. Classic mode sends credentials in the clear.
One connection carries commands and another carries the file. Because the classic form is cleartext and awkward through translators, administrators prefer encrypted alternatives.
Example: A client logs in on the control connection and then opens a data connection to download a file.
Ports
- TCP 21 — Control
- TCP 20 — Active-mode data
Common misconception
- Adding an S does not always mean the same thing. One variant is this protocol wrapped in encryption, and another is file transfer inside a secure shell.