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.