Timeout Error

[ServerGuy]

I'm receiving an error in the FTP logs relating to a timeout issue. Below is an excerpt from the FTP log. What seems to be happening is that a List command is given and the transfer completes but then the connection times out 3 minutes later.

My question is, what exactly on the back end is happening after the list command that's failing even though the transfer is complete? The profile retries and eventually has a list complete successfully. We are having some firewall issues so this can help us figure out what type of connection is having an issue.

8/18/2011 10:08:35 AM SOCKET REPLY:
150 Transferring directory
226 Transfer completed


8/18/2011 10:11:35 AM EclSocketError: Timeout error occured, code -1
8/18/2011 10:11:35 AM FTPListDirectory returned
8/18/2011 10:11:35 AM FTPListDirectory exception: Timeout error occured
8/18/2011 10:11:35 AM FindFirst: ftp://ftp.oursite.com/something/outgoing/*: retrying after EclSocketError "Timeout error occured"
8/18/2011 10:11:35 AM GetTheListing(CheckConn:TRUE)
CMD: PWD

[superflexible]

It seems to be a passive mode routing problem on the server side.

As you probably know, for Passive Mode, a lot of ports have to be forwarded to the server because the port for transfers is randomly chosen from a range of ports. This range can be specified in the FTP server software and it must match the range of forwarded ports in the router that connects the FTP server with the Internet. Maybe a part of that range is not forwarded, resulting in some transfers being successful and others not.

What you can also do is let it download a recursive listing by choosing the FTP Listing Command Automatic or LIST -alR. Then it will fail less often because ideally, it will need only one FTP LIST command.