FTP Over SSL (FTPS and FTPES)

---

• another way to secure FTP is to use TLS
  • two means of configuring FTP over TLS:
    • explicit TLS (FTPES)
      • used the AUTH TLS command to upgrade an insecure connection established over TCP port 21 to a secure one
      • protects authentication credentials
      • data connection for file transfer can be encrypted using PROT command
      • preferred method
    • implicit TLS (FTPS)
      • negotiate a TLS tunnel before the exchange of any FTP commands
      • uses TCP port 990 for the control connection
      • tricky to configure when there are firewalls between the client and server