SFTP Connection Tester — Verify Your Server Before You Transfer

Wondering whether your SFTP server will actually accept your credentials before you start a big transfer? This tool performs a single handshake check: it connects to your server over SFTP, verifies your username and password, confirms the SSH host key, and stops right there. Success means the connection side of your setup is sound — so you can move on to the real transfer with confidence.

Connect Now — transfer files from your browser

Why test an SFTP connection first?

Most "I can't connect to my server" problems are small and mechanical — the wrong host, a changed password, a firewall that will not let port 22 through, or a host key the server no longer matches. Each one wastes time and, more importantly, interrupts a transfer you were already counting on. A connection test isolates the problem: it tells you whether your SFTP server accepts your credentials at all, before you commit to uploading or downloading anything. If the handshake succeeds, the connection side of your setup is working; if it fails, the error tells you exactly which layer to look at — authentication, reachability, or the server's key.

How this connection tester works

You enter your host, port, username, password and (optionally) a starting folder, and the FilePort Pro server attempts a real SFTP handshake on your behalf. It uses the same SFTP stack as the FilePort Pro client, including the same host-key verification that guards against man-in-the-middle attacks. On success it returns the server's host-key fingerprint and the time the handshake took. Crucially, the test stops after the handshake: it confirms your credentials, then closes the connection immediately. It does not open the folder, list files, or check whether you can read or write — that is what a real connection is for.

Honest notes about privacy and what this proves

This tool is the most sensitive one on the site because it handles your SFTP credentials, so it is worth being precise. First, the check routes through FilePort Pro's servers, not your own computer — your browser sends the details to our API and our server makes the connection. Second, your credentials exist only in that request and in memory for the instant of the handshake: they are never stored and never logged, and the connection is closed immediately afterwards. Third, this tool tests SFTP only — never plain FTP, which sends credentials in the clear. And fourth, a successful handshake is not proof that you can read or write files there; the tool deliberately does not check permissions. For the full picture of how the app handles your data, the security page and the privacy policy cover it in detail.

What SFTP is: file transfer over SSH

SFTP (SSH File Transfer Protocol) is a way of moving files that runs inside an SSH connection — the same secure channel used for secure shell logins. Everything is encrypted: your username, your password, and your files as they travel. That's the key difference from classic FTP, which sends your login and data in the clear. SFTP normally uses port 22; FTP uses port 21. If your host gives you an "SFTP" or "SSH" login, you're connecting on 22, not 21.

What this connection test actually measures

This test makes a real SFTP connection to your server from FilePort Pro's servers. It checks that port 22 (or your custom port) is reachable over TCP, completes the SSH host-key handshake (which guards against man-in-the-middle attacks), and then verifies your username and password — after which it stops immediately. So a success really does confirm your credentials are accepted. What it can't tell you: it does not test whether you can list, upload, or download files (those are separate permissions), and it is SFTP-only — it never tries plain FTP.

Why a connection test can fail even with correct credentials

A failure doesn't always mean your password is wrong. Common causes: you're testing port 21 when the host runs SFTP on 22 (or another custom port); SSH/SFTP is not enabled on the host (some plans are FTP-only, or SSH must be switched on first); a firewall or security group blocks inbound port 22; the account allows key-only authentication so password login is refused; the host key changed (after a server rebuild, for example), which a strict client rejects; or the host is rate-limiting repeated login attempts.

How to troubleshoot a failed SFTP connection test

Confirm you're using port 22 (or your host's custom SSH port) and not 21. Check the server's firewall and, on a cloud host, its security group inbound rules — our AWS EC2 SFTP guide shows how to open TCP 22. Make sure SSH/SFTP is enabled on the account, and find out whether the server allows password logins or only SSH keys. If port 22 itself is blocked, resolve that first — the FTP port checker can confirm reachability. Full guide: SFTP connection errors — what "host key verification failed," "permission denied (publickey)," "connection refused," and "timed out" mean and how to fix each one. Then, once the test passes, connect for real with the web SFTP client, or, if your host offers plain FTP instead, the web FTP client.

Frequently asked questions

Is my password stored anywhere?

No. Your credentials travel only in the request to the test endpoint, exist in memory for the instant the handshake is checked, are never logged or stored, and the connection is closed immediately after the test completes.

What does a successful test actually prove?

A success means the SFTP server accepted your credentials and completed the SSH/SFTP handshake. It does not prove you can read or write files there — permission to list, upload or download is separate and is not checked by this tool.

Can I use this to test plain FTP?

No. This tool tests SFTP connections only. Plain FTP sends your username and password in the clear, so it is deliberately not supported here — we never transmit FTP credentials over an unencrypted channel.

How is this different from the FilePort Pro client?

This tester performs a single handshake check and stops right after — it does not open a browsing session, register a connection, or let you transfer files. The FilePort Pro client is the full tool you use when you are ready to actually browse, upload and download.

What's the difference between SFTP and FTP?

SFTP moves files over an encrypted SSH connection (usually port 22), while plain FTP sends your login and data in the clear (usually port 21). SFTP is more secure, which is why we recommend it.

Why does my test fail even though my password is correct?

A failed test isn't always a wrong password. It can mean SSH/SFTP isn't enabled on the host, port 22 is blocked by a firewall or security group, the server allows only SSH-key logins (no password logins), or the host key changed and is being rejected. See the troubleshooting section above.

What port does SFTP use?

SFTP uses port 22 by default — the standard SSH port. Some hosts run SSH on a custom port, in which case you connect to that instead. Port 21 belongs to plain FTP, not SFTP.

Handshake looks good? Now connect for real

Once you know your SFTP credentials are accepted, use FilePort Pro — a free, ad-supported SFTP client that runs right in your browser with nothing to install. Connect, browse, upload and download, with the same host-key verification you just saw here and credentials that are never stored.

Testing a plain-FTP server instead? Try your connection in the browser with the free web FTP client.

Connect Now — transfer files from your browser

See how to connect to your host — for example DigitalOcean SFTP or Hostinger SFTP.

Explore the other free tools: FTP port checker, SFTP command generator, transfer time calculator, checksum calculator and the ftp:// URL parser — or see all of them on the tools hub. Want to know exactly how the app handles your data? Read the security page and the privacy policy.