(Effective February 2013 - If your site is hosted on a Windows server, please read this article)
Many FTP download/upload errors and connection issues are caused by brief network outages or incorrect routing of FTP traffic. These types of issues are often intermittent and difficult to reproduce, diagnose, and troubleshoot. However, due to the large increase in network security, some FTP errors may be resolved by changing your FTP settings.
Depending on your FTP client, any firewalls or routers your machine is behind, and anti-virus software that you run on your machine, you may encounter errors when connecting to your FTP server or using FTP commands. For security reasons, many users may be behind a firewall (or even have a software firewall installed on their local machines) or router that restricts the types of connections that can be made.
In some cases there may be a firewall or router that restricts your connections that is external to your local network, such as devices maintained by your ISP or other transit provider between your network and Intermedia. Just because you do not have any active filtering on your network does not mean that your connection is not impacted by this type of filtering.
There is also an increase in anti-virus software packages that can scan and intercept FTP connections as well. Due to these security settings, you may find that you are unable to FTP to your server with your default FTP settings.
While there are many custom errors that your FTP client may return, if you receive any of the errors below, or if your connection simply times out when you use the "ls", "put" or "get" commands, you may need to adjust your passive mode setting.
425 Can't build data connection: Connection timed out
425 Can't open data connection
426 Connection closed; transfer aborted
503 No port command Issued first
In most cases these errors indicate that you need to set passive mode to ON. However, depending on your network connection, firewall, or router, you may actually need to disable passive mode. Information on where to change the passive mode setting for some common clients is included below.
Internet Explorer: To make this change in Internet Explorer, go to the Tools menu and choose Internet Options. In the Internet Options window, click the Advanced tab. Scroll down to find an option labeled Use Passive FTP, and check or uncheck the box.
Dreamweaver: Macromedia has published an FTP troubleshooting guide and information on how to change settings in DreamWeaver in their Knowledge Base.
WS FTP LE: On the Session Properties -- Advanced tab, select or unselect the checkbox labeled Passive Transfers.
Windows Command Line FTP: If using the Windows command-line FTP, you will need to enter "quote PASV" at the FTP- prompt (once you are connected to the server) before you begin performing any directory listings or file transfer operations (i.e.: ftp- quote PASV). The "quote" argument is the same as the "literal" argument, and uses the same syntax. Please note that depending on your own network settings, this option may not work.
Unix/Linux Shell: On most recent Unix and Linux releases, the FTP client built into the shell does have support for passive mode. You can type in "passive" at the FTP prompt (once you are connected to the server). Some clients also have a "pftp" command that automatically starts the FTP client with passive mode enabled.
If you are still having problems, please contact firstname.lastname@example.org and be sure to include specific details so we can help you resolve as quickly as possible.