Copy an FTP Server to the Cloud Without Running FileZilla for a Week

How to connect an FTP server to CloudsLinker

FTP is a server-parameter connection. There is no OAuth handshake; you enter the details you would give FileZilla, plus an optional connection cap, and CloudsLinker checks them against the server before saving.

Before you start

• A reachable host. Port 21 (or whichever port the server uses) and the server’s passive port range must be open to the public internet. Test from outside your own network with a desktop client in passive mode; if a directory listing hangs there, it will hang for CloudsLinker too.
• A plain-FTP login. The connector cannot negotiate TLS, so an account that is forced to FTPS will be rejected at login. Where the host also offers SSH, use the SFTP connector for that account instead.
• The per-IP session limit. Look it up in the host’s documentation or control panel (cPanel lists it under FTP Server Configuration; vsftpd uses max_per_ip). You will enter it as the connection cap.
• A start path, if you want CloudsLinker limited to one directory such as /public_html/uploads.

Connection steps

1. Sign in at app.cloudslinker.com, open Add Cloud and choose FTP.
2. Display name is pre-filled with “FTP”. Rename it to something you will recognise later, for example “Old cPanel host”.
3. Host: hostname or IP address, without ftp:// and without a port.
4. Username and Password: the FTP account. For an anonymous archive use anonymous and an e-mail address.
5. Port: pre-filled with 21; change it only if the server listens elsewhere.
6. Access Path (optional): leave empty to start at the account’s root, or enter a directory.
7. Max concurrent connections (optional): leave empty (unlimited) or enter the server’s per-IP limit, from 2 to 64. Enter 2 for a home NAS that allows two sessions.
8. Click I got it, Authorize Now FTP. CloudsLinker logs in immediately and probes the server’s features. On success the page reloads and the server appears under My Linkers; on failure the error is shown and nothing is saved.

Choosing the connection cap

The cap is the total number of FTP sessions CloudsLinker will hold open to this server at once. CloudsLinker reserves one and splits the rest between file transfers and directory checks:

• Cap 2: 1 transfer, 1 check, and the whole tree is checked before copying starts.
• Cap 4: 1 transfer, 2 checks.
• Cap 8: 3 transfers, 4 checks.
• Cap 16: 7 transfers, 8 checks.
• Empty or 0: no limit; CloudsLinker uses its normal parallelism, which is right for a dedicated server you control.

If both the source and the destination of a task are FTP servers, the smaller of the two caps applies to the whole task.

Creating the first transfer task

Open Transfer, choose a folder on the FTP server as the source and a folder in the destination cloud as the target. Add extension and size filters if needed, then run the task once or schedule it weekly or monthly. The task page shows each file’s status, so a file the host dropped mid-transfer can be retried on its own.

Revoke access

Delete the FTP entry under My Linkers to remove the stored login from CloudsLinker. On the server side, change the FTP account’s password or delete the account; FTP has no tokens, so a password change is the only revocation that matters.

FTP limits and behaviours you should know

FTP is a protocol rather than a hosted service, so most ceilings come from your server. These are the ones the CloudsLinker connector itself sets or depends on:

• Authentication: username and password; anonymous logins work where the server allows them.
• Encryption: none. Explicit FTPS (AUTH TLS, port 21) and implicit FTPS (port 990) are not selectable.
• Transfer mode: passive only, EPSV first and PASV as fallback; the server’s passive port range must be open.
• Connection cap: optional, 0 or 2 to 64; 1 is rejected. Applied when the FTP server is source or destination.
• Integrity check: size, plus modification time when the server supports it. No checksums.
• Timestamps: read via MLSD or MDTM; written via MFMT only (not on vsftpd).
• Listings: MLSD when advertised, otherwise LIST; UTF-8 file names when the server advertises UTF8.
• Idle connection timeout: 60 seconds; low-level errors retried twice per file.
• Maximum file size: none imposed by the connector. Limits come from the server filesystem (ext4 16 TiB per file) and the destination: OneDrive 250 GB, Google Drive 5 TB, Amazon S3 5 TB per object.
• Scheduling: run once, weekly, or on selected days each month.
• Filters: file extension include list, minimum and maximum size in MB.
• Traffic allowance: free account 10 GB per month for testing; Lite 800 GB per month with rollover at $3.33 per month on yearly billing; Unlimited at $5.83 per month on yearly billing; Lifetime Unlimited $138.80 one-time.

Sources: RFC 959: File Transfer Protocol, RFC 2428: FTP extensions for IPv6 and NATs (EPSV), RFC 4217: Securing FTP with TLS, vsftpd.conf manual: max_per_ip, force_local_logins_ssl, mdtm_write, EnterpriseDT: SFTP and FTPS ports and the passive range, CloudsLinker pricing.