Introducing NOP on command PORT #2

[POLAURENT]

thanks @botg for your answer ,

Introducing NOP on command PORT - FileZilla Forums viewtopic.php?f=6&t=53236

you've locked the topic so i cannot answer in it, so i open a new one.

What i've asked is about to introduce a feature to correct the faulty behavior of NAT router, it doesn't seems that the RFC states that the Server should stay mute during data transfer ..

[botg]

RFC 959 mandates that the client cannot send actual data over the control connection while a transfer is ongoing.

[boco]

I'm pretty sure the same is true for FTP server software. An FTP server can only react to client requests, it must never send any data entirely on its own.

You already identified the router as the faulty device. Here's where you should start fixing.