Filezilla problems with large files

But since the control connection got dropped without notification, the reply never arrives and eventually the connection will timeout. In an attempt to solve this problem, the TCP specifications include a way to send keep-alive packets on otherwise idle TCP connections, to tell all involved parties that the connection is still alive and needed.

However these keep-alive packets should not be sent more often than once every two hours. Therefore, with added tolerance for network latency, connections can stay idle for up to 2 hours and 4 minutes. However, many routers and firewalls drop connections that have been idle for less than 2 hours and 4 minutes. Depending on your router model, you can either forward a range of ports or you need to forward all ports individually.

Valid ports can be from 1 to ; however, ports less than are reserved for other protocols. It is best to choose ports greater than or equal to for active mode FTP. Due to the nature of TCP the underlying transport protocol , a port cannot be reused immediately after each connection. Therefore, the range of ports should not be too small to prevent the failure of transfers of multiple small files. A range of 50 ports should be sufficient in most cases. Warning: The content of this section is outdated and needs to be adapted to apply to FileZilla Server version 1.

Setting up the server is very similar to setting up the client, with the main difference being that the roles of active and passive mode are reversed. A common mistake, especially by users with NAT routers, is in testing the server. If you are within your local network, you can only test using the local IP address of the server. Using the external address from the inside will probably fail, and one of the following may happen:. Even if the test works, there is no guarantee that an external user can really connect to your server and transfer files.

The only reliable way to test your server is to try connecting from an external system, outside of your LAN. Make sure FileZilla Server is allowed to establish outgoing connections to arbitrary ports, since the client controls which port to use.

On the local end of the connection, FileZilla Server tries to use a port one less than that of the control connection e.

However, this is not always possible - so don't rely on it. The server configuration is very similar to client configuration for active mode. In passive mode, the server opens a socket and waits for the client to connect to it. By default, FileZilla Server asks the operating system for the machine's IP address, and for a free port number. This configuration can only work if you are connected to the internet directly without any NAT router and if you have set your firewall to allow incoming connections on all ports greater than If you have a NAT router, you need to tell FileZilla Server your external IP address or passive mode connections will not work with clients outside your local network:.

If you do not want to allow incoming connections on all ports, or if you have a NAT router, you need to tell FileZilla Server to use a specific range of ports for passive mode connections.

Valid ports can be from 1 to , however ports less than are reserved for other protocols. Hence the range of ports should not be too small or transfers of multiple small files can fail.

Unfortunately, many personal firewalls and consumer routers are flawed or in some cases, even actively sabotage FTP e. SMC Barricade V1. First of all, as with all software, you should keep everything updated. This includes the firewall software as well as the firmware version of your router.

If that does not help, you might want to try to uninstall your firewall to see what happens. Simply disabling your firewall might not work, as some firewalls cannot be fully disabled. In particular, most firewalls install virtual device drivers which cannot be disabled other than by uninstalling them. Also check for hidden firewalls. Programs such as virus scanners often have firewall functionality as well. If possible, try to connect directly to the internet without a router by plugging your computer directly into your modem.

If you are trying to setup a server and it works fine within your LAN but is not reachable from the outside, try changing the listening port. Some ISPs don't like their customers to host servers and they may block ports with numbers under Another issue may occur if you are hosting an FTP server on default port Try using another non-default port for your FTP server.

If you encounter "cannot open data connection" on a random basis i. When your ftp connections are running in pasv mode, the client-side outgoing ports are selected randomly and some of those randomly selected ports may be blocked by the anti-virus software.

To identify this problem, read your anti-virus log on the client. In general, any software that can block certain ranges of outgoing ports such as PC firewalls can cause similar FTP grief. As mentioned above, FTP uses two TCP connections: a control connection to submit commands and receive replies, and a data connection for actual file transfers. It is the nature of FTP that during a transfer the control connection stays completely idle.

The TCP specifications do not set a limit on the amount of time a connection can stay idle. Unless explicitly closed, a connection is assumed to remain alive indefinitely.

However, many routers and firewalls automatically close idle connections after a certain period of time. Worse, they often don't notify the user, but just silently drop the connection. Try increasing the timeout value to about double the time it usually takes to transfer KB. The headstart is caused by the internal socket buffer of Windows.

I changed the timeout to 45 seconds, and could then transfer a large file, however, the progress bar is not smooth. It "jumps" instead of being smooth. Is there any way to have smooth progress bar updates like I do with 2. In the next version of FileZilla you will be able to manually adjust the "Socket recv buffer size" and "Socket send buffer size" in the settings file. Powered by Trac 1. Login Preferences Register Forgot your password? Home Timeline Search and View Tickets.