filezilla Failed to create listen socket on port 21 for IPv4 解决办法
小编帮一个客户配置filezilla的时候，提示filezilla Failed to create listen socket on port 21 for IPv4，原来是因为21端口被占用了，换个端口就可以了，更详细的在这篇文章里面，有兴趣的朋友可以来看看
windows server 2003 使用filezilla 时，安装好之后，点击“Active”可能会报下面的错
Creating listen socket on port 21...
Failed to create listen socket on port 21 for IPv4
Failed to create listen socket on port 21 for IPv6
Failed to create a listen socket on any of the specified ports. Server is not online!
Creating listen socket on port 21...
Failed to create listen socket on port 21 for IPv4
Failed to create listen socket on port 21 for IPv6
Failed to create a listen socket on any of the specified ports. Server is not online!
Creating listen socket on port 21...
Failed to create listen socket on port 21 for IPv4
Failed to create listen socket on port 21 for IPv6
具体的解决办法：
一般这种情况是因为21 端口被占用，先用这个命令查询一下
netstat -abn |findstr 21