I have implemented my own client, but I am unable to communicate properly with your server

[sennin]

My client will only start establishing the data connection after receiving a 150 response. I've researched extensively, and this seems to be in accordance with the standard. However, your server sends the 150 response only after the service connection is established; otherwise, it times out and sends a 425 response. So, am I mistaken, or is your server not compliant with the rfc standard?

[sennin]

I wait for the 150 response before establishing the connection, while your server waits to send the 150 response after a successful connection is established. This has led to a deadlock. Which one is more in compliance with the standard

[botg]

Cannot reproduce, FileZilla Server immediately sends out a 1yz reply after receiving a transfer command, regardless of the state of the data connection.

Note that technically the 1yz reply may even be absent, the protocol doesn't require it. Its presence is more like a customary convention.

[sennin]

3q，I'll make some more changes to my code.