Secure FTP vs. SFTP — Which to use?
Short answer: prefer SFTP for most modern deployments; choose FTPS (often called “Secure FTP”) only when you need TLS/X.509 certificate interoperability or must interoperate with legacy FTP/enterprise systems.
Key differences
- Protocol layer:
- SFTP = SSH File Transfer Protocol (runs over SSH, usually TCP 22).
- FTPS = FTP over TLS/SSL (extends FTP, uses TLS; control usually on 21, implicit on 990).
- Ports & firewall:
- SFTP: single port (simpler for NAT/firewalls).
- FTPS: control + separate data channels (active/passive) require additional ports and NAT handling.
- Authentication:
- SFTP: username/password or SSH keys (public-key auth).
- FTPS: server and optional client X.509 certificates (useful for PKI-based environments).
- Security model:
- Both provide strong encryption if properly configured. SFTP secures all traffic by default; FTPS can fall back to unencrypted FTP if misconfigured (explicit vs implicit modes matter).
- Compatibility & tooling:
- SFTP widely supported on Unix/Linux and modern tooling and cloud services.
- FTPS is often required where X.509 certificates or legacy FTP integrations are mandated (some Windows/enterprise setups).
- Operational considerations:
- SFTP: easier through firewalls, better for automation, scriptable, SSH key management required.
- FTPS: better when certificate trust chains and CA-managed certs are policy requirements; more complex firewall/NAT config.
When to choose SFTP
- You need single-port, firewall/NAT-friendly transfers.
- You prefer SSH-key automation or integrate with Unix/Linux/DevOps tools.
- You’re transferring sensitive data across untrusted networks and want simpler deployment.
When to choose FTPS (Secure FTP)
- Your organization requires X.509 certificate authentication or integration with PKI.
- You must interoperate with legacy FTP infrastructure that expects TLS/SSL.
- Compliance or partner requirements explicitly specify FTPS.
Practical guidance
- Default to SFTP unless a specific
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