iptables -A INPUT -p tcp -m state --state NEW --dport 20 -j ACCEPT
iptables -A INPUT -p tcp -m state --state NEW --dport 21 -j ACCEPT
iptables -A INPUT -p tcp -m state --state NEW --dport 10000:20000 -j ACCEPT

vsftpd.conf 수정부분

pam_service_name=vsftpd
userlist_enable=YES
session_support=YES
#enable for standalone mode
listen=YES
tcp_wrappers=YES
pasv_enable=YES
pasv_promiscuous=YES
port_promiscuous=YES
use_localtime=YES
#local_umask=022
hide_ids=YES
one_process_model=NO
pasv_min_port=10000
pasv_max_port=20000
#전송속도 제한(byte단위)
anon_max_rate=10000000
local_max_rate=10000000

lsmod 사용중에 느려지는 모듈 삭제
rmmod ip_conntrack_ftp