FTPS with PASV not working from internet side.

[Steven]

I've set up my server to enable implicit FTPS (port 990) but the unsecure connection method is still accepted too.

When I try to connect to the server using unencrypted method, everything works fine, no matter if I'm local or internet originated.
But for FTPS, it's different. From local network, everything is fine, from the internet side the connection goes as far as switching to passive (PASV) mode. From there on, connection hangs.
I checked the logs on my client and believe to know the cause (but not the solution): Upon switching to PASV mode, my client is given the local IP-address instead of the real 'outside' ip-address.
It is as if the server suddenly believes this connection to be on the local net and thus not send the 'real' address.

I.o.w. when using FTPS and PASV mode enabled for all but local connections, Filezilla server is still sending the local ip-address together with the port nr to use for the passive connection to an external client trying to connect.
This isn't so for unsecure connections and therefore I believe this to be a bug.

[Tim Kosse]

Please read ​https://wiki.filezilla-project.org/Network_Configuration