Status: Connection established, waiting for welcome message...  
Response:   220 (vsFTPd 2.3.0)  
Command:    USER vfjeans  
Response:   331 Please specify the password.  
Command:    PASS ********  
Response:   230 Login successful.  
Command:    OPTS UTF8 ON  
Response:   200 Always in UTF8 mode.  
Status: Connected  
Status: Retrieving directory listing...  
Command:    PWD  
Response:   257 "/"  
Command:    TYPE I  
Response:   200 Switching to Binary mode.  
Command:    PASV  
Response:   550 Permission denied.  
Error:  Failed to retrieve directory listing  

Esto es debido a que no tienes los puertos abiertos y te hace falta el modulo del kernel:

nf_conntrack_ftp

http://www.linuxquestions.org/questions/linux-software-2/nf_conntrack-nf_conntrack_ftp-what-is-the-difference-778200/#post3805336