Ftp – Server sent passive reply with unroutable address when connecting to FTP site with FileZilla

I suggest you try to locally on the server using Windows' FTP or another installed client. This way you will see if it's network/firewall issue or an issue with the configuration of the FTP server. Also check Filezilla server's log files if the commands.

If it depends on the firewall, here is a TechNet article that could help: How to Configure Windows Firewall for a Passive Mode FTP Server. But you wrote that the Windows firewall is off, so I suppose it is a problem of the external firewall/router (also check the client side).

On Windows Server 2003 and Windows XP the default range of ephemeral ports used by client applications is from 1025 through 5000. Under certain conditions it is possible that the available ports in the default range will be exhausted.

netstat -n or netstat -b to see active connections

Increase the upper range of ephemeral ports that are dynamically allocated to client TCP/IP socket connections.

1. Start Registry Editor.
2. Browse to, and then click the following key in the registry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. On the Edit menu, click New, DWORD Value, and then add the following registry value to increase the number of ephemeral ports that can by dynamically allocated to clients: Value name MaxUserPort Value data
4. Close Registry Editor.

Note: You must restart your computer for this change to take effect.

Note: Increasing the range of ephemeral ports used for client TCP/IP connections consumes Windows kernel memory. Do not increase the upper limit for this setting to a value higher than is required to accommodate client application socket connections so as to minimize unnecessary consumption of Windows kernel memory.