ProFTP Archives

How to fix “MLSD unable to build data connection” in ProFTP

I’ve come across an odd problem today on a server that’s been working fine for all kinds of FTP traffic for many years. Turns out that today, FileZilla started complaining about explicit TLS connections (when available) and gave the following error message: 425 MLSD unable to build data connection: operation not permitted Clients could still … Read more

How to allow resuming FTP uploads in Plesk and ProFTP

ProFTP has a handy feature that lets uploads resume if they were interrupted, much like Safari downloads. This feature has to be enabled both on the server and the client. By default however, resuming uploads are disabled for security reasons – a wise precaution if anonymous uploads are allowed to a server. Here’s how to … Read more