Doesn't work. I redirected all my errors to /var/log/messages, so here's what I get when I try to connect Filezilla to that server.
May 23 16:48:58 c7-server kernel: +++ IPv4 packet rejected +++ IN=enp0s3 OUT= MAC=08:00:27:00:00:03:d4:85:64:b2:b2:1b:08:00 SRC=192.168.2.2 DST=192.168.2.12 LEN=60 TOS=0x00 PREC=0x00 TTL=64 ID=30737 DF PROTO=TCP SPT=51474 DPT=38714 WINDOW=29200 RES=0x00 SYN URGP=0
FTP uses two ports - in active mode the server uses 21 for command and 20 for data after the initial connection. In passive mode it uses 21 for command and a high random port number for data. What is happening is that you are blocking the high port number. (Yes, I know that's a gross simplification.)
You could use active transfer and open port 20, or you could use passive, which is more "secure", and allow connections to high port numbers.
Search for active vs passive ftp for more info.
P.