vsftpd在本机上可以访问，在其它wiodows机器访问不了，何故？

xxbt

vsftpd.conf如下：
# Example config file /etc/vsftpd.conf
anonymous_enable=YES
local_enable=YES
write_enable=YES
local_umask=022
anon_upload_enable=YES
anon_mkdir_write_enable=YES
dirmessage_enable=YES
xferlog_enable=YES
connect_from_port_20=YES
这里的20端口什么意思那？默认的不是21口么？不理解

#chown_uploads=YES
#chown_username=whoever

xferlog_file=/var/log/vsftpd.log
xferlog_std_format=YES
idle_session_timeout=600

#data_connection_timeout=120
# It is recommended that you define on your system a unique user which the
# ftp server can use as a totally isolated and unprivileged user.
#nopriv_user=ftpsecure

async_abor_enable=YES
ascii_upload_enable=YES
ascii_download_enable=YES

#ftpd_banner=Welcome to blah FTP service.
#deny_email_enable=YES
#banned_email_file=/etc/vsftpd.banned_emails
#chroot_list_enable=YES
#chroot_list_file=/etc/vsftpd.chroot_list
#ls_recurse_enable=YES

pam_service_name=vsftpd
userlist_enable=YES
#enable for standalone mode
listen=YES
tcp_wrappers=YES
max_per_ip=2

请大虾指点小弟一下，不胜感激！！ :thank

synn

20是传输端口,21是控制端口.
你的防火墙允许21进入了没有?

xxbt

怎么设置防火墙那？另外端口的问题我还是不太明白，请详细解释一下好吗？多谢了
//bow