sox-proftpd

filezilla:
Status: Connecting to 193.105.163.202:21...
Status: Connection established, waiting for welcome message...
Status: Insecure server, it does not support FTP over TLS.
Status: Logged in
Status: Retrieving directory listing...
Command:    PWD
Response:   257 "/" is the current directory
Command:    TYPE I
Response:   200 Type set to I
Command:    PORT 46,234,78,40,150,53
Response:   200 PORT command successful
Command:    MLSD
Error:  Connection timed out after 20 seconds of inactivity
Error:  Failed to retrieve directory listing

telnet:
tomba@Tomba-ZBook:~$ telnet sox.cybershark.rs 21
Trying 193.105.163.202...
Connected to sox.cybershark.rs.
Escape character is '^]'.
220 FTP Server ready.
USER testfixbug
331 Password required for testfixbug
PASS *********
230 User testfixbug logged in
CWD /
250 CWD command successful
PORT 46,234,78,40,150,53
421 Idle timeout (600 seconds): closing control connection
Connection closed by foreign host