Can't use active ftp from lxd container

strange thing.
tested with lxd 4.0.3 and 4.4, ubuntu18 host, ubuntu20.04/18.04 container.

unable to use active ftp connexion from the container.
only passive connection work.
can connect, enter user, password, but dir command block and return error, and disconnect.
the only way to work is to enter pass command to set passive ftp.
tried from host to same external ftp servers, and active ftp work.
problems occurs only from the container.
problem with port 20…?

container creation from fresh ubuntu 18.04 updated/upgraded:
snap install lxd --channel=4.0/stable (also tested latest/stable)
lxd init (all defaut config)
lxc launch ubuntu:20.04 store
lxc exec store – /bin/bash
apt update
apt upgrade
ftp external server
Connected to server.
Name : username
331 Password required for username
230 User username logged in
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> dir
200 PORT command successful

and wait to

425 Unable to build data connection: Connection timed out
450 LIST: Connection timed out

This is quite common in my experience as due to nat use in the clients the ftp server can’t connect back to client ip. I always use passive.

but i tryed same thing on host, and ftp active work.
i can’t believe that they aren’t a working solution…
do they have any other port to include in proxy rule ??

Is the FTP server you’re trying to connect to using an LXD proxy in NAT mode?

And is the container that is trying to connect to the server also behind an LXD outbound NAT?