ability to connect to FTP server depends on IP address

[tholen]

Home network, three computers. Desktop computer with FTP server connected to router via a wired connection. Two laptop computers with Filezilla FTP clients connected to router via wireless connections; one runs Windows XP and an older Filezilla client, while the other runs Windows 7 and has the latest Filezilla client 3.11.0.2. Everything is DHCP.

Router dynamically assigned 192.168.0.101 to the desktop machine. Both laptop Filezilla FTP clients have entries in the Site Manager to connect to host 192.168.0.101. Both worked just fine for months and months.

Following a recent power outage, router dynamically assigned 192.168.0.100 to the desktop machine with FTP server. Site Manager on the Windows XP machine was updated to point to 192.168.0.100, and it works. Site Manager on the Windows 7 machine was updated to point to 192.168.0.100, but sometimes it works and sometimes it does NOT work. When it does NOT work, the router has assigned the Windows 7 laptop 192.168.0.101 (the previous address of the desktop FTP server). When it does work, the router has assigned the Windows 7 laptop some other IP, such as 192.168.0.103 (the most recent time it worked). When it fails, the messages are "Connecting to 192.168.0.100", "Connection timed out after 20 seconds of inactivity", and "Could not connect to server".
The automatic retry yields the same set of errors. Meanwhile, the FTP server on the desktop machine shows no attempt to connect from another machine on the home network. And the Windows XP machine has absolutely no trouble connecting.

Speculation: something in Filezilla "remembers" that the FTP server used to be 192.168.0.101 (even though the IP was changed in the Site Manager), so when the router assigns 192.168.0.101 to the Windows 7 laptop, Filezilla tries to connect to "itself" and fails. When the router assigns 192.168.0.103 (or 102, or 104, or 105) to the Windows 7 laptop, everything works just fine.

I suppose I could learn how to configure the router so that it forces a particular IP onto a machine and that would get around the problem, but it sure looks like there is a bug in Filezilla.

[Tim Kosse]

FileZilla doesn't remember past IP addresses.

Are you using any firewalls that might block the connection depending on IP address?

[Alexander Schuch]

No reply for more than 28 days.