Teensy randomly hangs when uploading file via ftp (non deterministic)

If I remember correctly (and my memory is very weak on this), the client was terminating(closing?) the PASV, but the Teensy FTP server wasn't releasing the sockets and/or resources.
thanks for answering, now i think that helps a bit. But did you try to open in ftp in Active mode ?

Alfter all i want to reach the goal to have an Teensy 4.1 with LittleFs and an ftpd that sends and recives data form an ftp client.
i tested Simpleftp but that was working only with sdfat and after some writes ans list of dir it stuck sendign data.

So i serch for a working ftp server on Teendsy 4.1.
I think that i could not make the ftpd code much clever but i can test.
Working client for me was FTPRush with the config that was in SimpleFtp server Doku. and in Active mode ist works better.

But i do not get that working without problems.

So is there no interest on ftp ? Or i am wrong ist thre a other way to bing files over Network to the T4.1 ?
I know there is an tftp but that protocol is very smal an dos not have all features like a ls / dir command that was very usefull.


i am stranded with my test. I User arduino IDE 1.8.19 and TD 1.56
Using the examble 1 and downloaded all form the links in the thread.
Compiled for T 4.1

The problem:

the vfs.h did not work with the new version of sd.h or sdfat.h or is there a newer version withch i did not find ?