Migrate to/from FTP / FTPS Servers (Hybrid Cloud Bridge)

What is FTP?

FTP — the File Transfer Protocol — was standardized in 1971 (RFC 114) and is one of the oldest protocols still in widespread production use, predating HTTP, SMTP, and even TCP/IP itself. Despite being functionally obsolete for new deployments (replaced by SFTP and HTTPS), FTP remains alive across millions of legacy webhost control panels, CDN origin servers, embedded device firmware, scientific data drops, music/video distribution endpoints, and government file exchanges. The protocol uses two channels — control on port 21, data on port 20 (active mode) or a passive port range (passive mode) — and was originally designed without encryption. FTPS (FTP over TLS) adds an encryption layer; SFTP (a different protocol entirely, over SSH on port 22) is the modern secure replacement and has its own CloudsLinker connector.

What makes FTP integration uniquely useful in 2026 isn't the protocol itself — it's that so much legacy infrastructure still exposes FTP as the only network access path. Web hosts (cPanel / Plesk), Linux VPS configurations, scientific instruments, surveillance cameras, embedded devices, and inherited corporate servers all routinely speak FTP and nothing else. CloudsLinker bridges these legacy endpoints to modern cloud storage: connect any FTP / FTPS server using host + credentials + port, then run scheduled migrations to Google Drive, OneDrive, S3, Wasabi, or B2. Particularly valuable for migrating off shared hosting before account closure, archiving CCTV footage from on-prem to S3, or piping scientific data drops into a cloud-based analytics pipeline.

Key features of FTP

Standardized in 1971 (RFC 114)

FTP predates HTTP, SMTP, and even TCP/IP. 50+ years of deployment means more legacy systems speak FTP than any other file-transfer protocol. Control channel on port 21, data channel on port 20 (active) or passive range.

FTP is plaintext — use FTPS or SFTP

Vanilla FTP transmits credentials and file content in plaintext. Use FTPS (TLS-wrapped) when migrating sensitive data over untrusted networks, or use the dedicated SFTP connector (different protocol, SSH on port 22).

Passive mode default in 2026

Active mode requires the server to open inbound connections to your client — broken by virtually every modern firewall / NAT. Passive mode (client initiates both connections) is the default in 2026 and the only mode that works behind common NAT routers.

FTPS uses port 990 for implicit

FTPS-implicit: port 990 (TLS from connection start). FTPS-explicit: port 21 (TLS negotiated via AUTH TLS). CloudsLinker handles both.

No protocol-imposed file size limit

FTP itself imposes no file size limit. Practical caps come from server filesystem (e.g. ext4 max 16 TiB), reverse proxy timeouts, or destination cloud limits. Multi-GB transfers routine.

Passive port range firewall consideration

Passive-mode FTP requires the server's firewall to allow a configured passive port range (typically e.g. 50000–51000). Common deployment friction; CloudsLinker reports clearly when passive-mode handshake fails.

Why connect FTP to CloudsLinker

CloudsLinker connects to FTP and FTPS (FTP over TLS) servers using standard parameters: hostname, username, password, port (default 21), and optional initial path. The connector defaults to passive mode — the modern standard for firewall / NAT compatibility — but supports active mode where servers require it. FTPS is auto-detected when the server advertises TLS; explicit FTPS-only mode is also configurable. Once connected, transfers run server-to-server: CloudsLinker pulls bytes from the FTP origin and pushes them to the destination cloud directly, without staging on your device.

What you can do with FTP on CloudsLinker

FTP / FTPS as cloud bridge

Connect any FTP / FTPS endpoint and migrate to Google Drive, OneDrive, Dropbox, S3, Wasabi or B2 — server-to-server, passive-mode default.

Runs without your laptop

FTP transfers execute on CloudsLinker servers. Useful for slow legacy origins where the FTP transfer takes hours — your machine doesn't need to stay on.

Scheduled FTP-to-cloud sync

Hourly / daily / weekly schedules. Common for archiving CCTV / log / scientific-data servers that produce daily files into S3 cold archive.

Filter by path, type, age

Migrate only <code>/var/log/2026</code>, exclude files larger than the destination's cap, or sync only files modified in the last 30 days.

Common FTP transfer scenarios

Migrate legacy webhost (cPanel / Plesk) → S3 / Wasabi before shutdown

Shared-hosting customers who decide to leave cPanel / Plesk providers normally face a manual FTP-download-then-cloud-upload workflow taking days. CloudsLinker connects to the FTP origin, copies the entire site directory tree to S3 / Wasabi / B2 server-to-server in hours. Useful for migrations triggered by hosting provider shutdown, price hikes, or migration to static-site hosting (Cloudflare Pages, Netlify).

Archive CCTV / DVR footage from on-prem FTP → S3 Glacier

On-prem CCTV systems and DVRs frequently push daily footage to a local FTP folder. Schedule a CloudsLinker daily incremental from the on-prem FTP server to S3 Glacier Instant Retrieval ($0.004/GB) or B2 ($6/TB) — preserves footage long-term at low cost while freeing local DVR disk.

Scientific instrument data drops → cloud analytics pipeline

Lab instruments, telescopes, and IoT sensors often export to FTP folders as their only network output. CloudsLinker schedules ingest from the instrument's FTP into a Google Cloud Storage / S3 bucket where BigQuery / Athena can query the data.

Mirror FTP-distributed media (open-source ISOs, dataset repos) into commercial cloud

Open-source projects (Linux distros, scientific datasets, font repositories) often distribute files via FTP. CloudsLinker can mirror these into a private S3 bucket for faster internal access, immutable archive, or content-distribution networks.

Legacy enterprise B2B file exchange → Google Drive shared folder

Many enterprise B2B partners exchange files via FTP drops (PO files, EDI, financial reports). CloudsLinker watches the inbound FTP folder and copies new files to a Google Drive shared folder where the receiving team works — modernizing the workflow without changing the partner's FTP-only output.

How to connect FTP / FTPS to CloudsLinker

FTP uses server parameters: hostname, username, password, port (default 21), and optional initial path.

Before you start

Gather the connection details from your FTP server admin:

Hostname (e.g. ftp.example.org or an IP address)
Username and password (or anonymous if the server allows it)
Port (default 21 for FTP, 990 for FTPS-implicit)
Passive port range (your FTP server admin should have configured this — typically 50000–51000)
TLS / FTPS support — does your server require encryption? CloudsLinker auto-detects but explicit FTPS mode is configurable.

For sensitive workloads, prefer FTPS over plain FTP. For maximum security, use the dedicated SFTP connector instead (SSH-based, runs on port 22, single-port firewall-friendly).

Connection steps

In CloudsLinker, click Add Cloud → choose FTP.
Enter a display name (e.g. “Legacy webhost FTP”).
Enter the hostname and port (default 21).
Enter the username and password. For anonymous FTP, leave password blank or use an email-style placeholder.
(Optional) Enter an initial path (e.g. /htdocs/uploads) to scope the connection to a specific directory.
(Optional) Toggle FTPS if you need TLS encryption (recommended for credential safety on untrusted networks).
Click Confirm — CloudsLinker validates with a passive-mode handshake and shows the connection ready.

Passive mode is default

CloudsLinker uses passive mode by default — required for any setup where CloudsLinker is behind a NAT or firewall (always, in production). If your FTP server requires active mode for some legacy reason, contact CloudsLinker support to enable it.

Revoke access

To revoke CloudsLinker’s access: change the FTP user’s password on the server, or delete the dedicated FTP user account. CloudsLinker’s connection becomes immediately unusable. No token-revocation flow exists because FTP itself doesn’t use tokens.

FTP upload & download limits you should know

FTP is a protocol, not a service — limits depend entirely on the FTP server you’re connecting to:

Protocol-imposed file size: none. FTP itself has no per-file cap.
Server filesystem max: typically the filesystem’s hard limit (ext4: 16 TiB per file, NTFS: 256 TB). Most modern FTP servers handle multi-TB files.
Default FTP port: 21 (control). Active-mode data on port 20; passive-mode on a configured range.
FTPS-explicit: port 21, TLS negotiated via AUTH TLS command.
FTPS-implicit: port 990, TLS from the start of the connection.
SFTP (different protocol entirely): port 22 — use the dedicated SFTP connector, not this one.
Active vs passive mode: passive mode is the default in 2026 and the only mode that works through NAT / firewalls.
Encryption: plain FTP is unencrypted — credentials and file content travel in plaintext. Use FTPS or SFTP for sensitive data.
Bandwidth: server-side configurable (rate-limit directives in vsftpd / ProFTPD). No protocol-level cap.
Concurrent connections: server-side configurable (typically 5–50 simultaneous FTP sessions per user).
Authentication: static username + password. No OAuth, tokens, or 2FA in standard FTP. Some FTPS servers support client-cert auth.
Compatible with: vsftpd, ProFTPD, Pure-FTPd, FileZilla Server, Microsoft IIS FTP, and any RFC 959 / 4217-compliant FTP server.

Sources: SolarWinds: SFTP vs FTPS, GoAnywhere: SFTP vs FTPS, Files.com: Active vs Passive Mode FTP, JSCAPE: Setting up FTPS behind firewall / NAT for PASV.

FTP + CloudsLinker — Frequently Asked Questions

What's the difference between FTP, FTPS, and SFTP?

FTP: the original 1971 protocol, plaintext, port 21. FTPS: FTP wrapped in TLS encryption, ports 21 (explicit) or 990 (implicit). SFTP: a completely different protocol that runs over SSH on port 22 — not related to FTP at all despite the similar name. CloudsLinker has separate connectors for FTP/FTPS and for SFTP.

Do I need active or passive mode?

Passive mode in 99 % of cases. Active mode requires the server to open an inbound TCP connection back to your client — virtually always blocked by client-side firewalls and NAT. CloudsLinker defaults to passive mode and falls back to active only when explicitly configured.

What's the maximum file size FTP can transfer?

FTP itself has no protocol-imposed size limit. Practical limits come from: (1) server filesystem (e.g. ext4 max single file 16 TiB), (2) reverse-proxy / firewall timeout, (3) destination cloud's per-file cap. Multi-GB transfers are routine; multi-TB transfers work if all components support it.

Are my FTP credentials safe with CloudsLinker?

Username and password are encrypted at rest with AES-256 and decrypted only inside the active transfer worker. However: if you connect via plain FTP (not FTPS), credentials travel in plaintext from CloudsLinker to your FTP server — vulnerable to network sniffing. Use FTPS or SFTP for sensitive credentials.

How does CloudsLinker handle FTPS?

FTPS auto-detection: if your FTP server advertises TLS support (AUTH TLS response on port 21), CloudsLinker negotiates the TLS handshake transparently. For FTPS-implicit (TLS from start), use port 990 and select FTPS in the connector type. Both modes preserve confidentiality of credentials and file content in transit.

What about firewall configuration for passive mode?

The FTP server must be configured to use a known passive port range (e.g. 50000–51000) and have those ports open in its firewall. CloudsLinker initiates the passive-mode handshake; if the server's passive port range is blocked, the handshake fails with a clear error message. Contact your FTP server admin to open the passive range, or switch to SFTP (single port 22 — much easier through firewalls).

Can CloudsLinker schedule recurring FTP migrations?

Yes. Set hourly / daily / weekly schedules with delta sync — only files added or modified since the last successful run are copied. Useful for daily log archival, CCTV footage backup, or scientific-data ingest workflows.

Does CloudsLinker work with FTP servers behind a corporate VPN?

CloudsLinker's transfer infrastructure runs on the public internet. To reach an FTP server behind a corporate VPN, expose it via port forwarding (with strong authentication and IP allowlist) or migrate to a public-internet-reachable SFTP server. For air-gapped corporate FTP servers, CloudsLinker is not directly usable.

How fast can CloudsLinker pull from an FTP server?

Throughput depends entirely on (1) the FTP server's CPU/disk/uplink, (2) the network path between CloudsLinker and the server, (3) destination cloud's ingress speed. Typical sustained throughput is 50–500 GB/day per FTP connection — slow legacy hosts at the lower end, modern dedicated FTP servers at the upper end.

Is CloudsLinker an official partner of any FTP server vendor?

No — FTP is an open standard, not a vendor product. CloudsLinker uses the standard FTP / FTPS protocols defined by RFC 959 and RFC 4217. Compatible with vsftpd, ProFTPD, Pure-FTPd, FileZilla Server, Microsoft IIS FTP, and any RFC-compliant FTP server.

How do I revoke CloudsLinker's access to my FTP server?

Change the FTP user's password on the server side, or delete the dedicated FTP user account if you created one for CloudsLinker. The CloudsLinker connection becomes immediately unusable. There's no token-revocation mechanism specific to CloudsLinker because FTP itself uses static credentials.

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Conclusion

FTP is older than the modern internet but remains the only network protocol exposed by countless legacy systems — webhosts, CCTV servers, scientific instruments, B2B file-drop endpoints. CloudsLinker bridges these legacy endpoints to modern cloud storage with passive-mode default, FTPS auto-detection, and scheduled delta sync. Connect with host + credentials + port and start moving legacy data to S3 / Google Drive / OneDrive in minutes.

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