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