Problem with Dropped Connection

I have found that when I am using Cerberus FTP server and SmartFTP that my connection is dropped after 10 minutes when I am downloading a large file.

I put ethereal on the connection and here is what I found.

Either my ISP or my Router is droping the control socket because there is no traffic accross it for 10 minutes. SmartFTP sees this as a terminating connection eventhough data is still being sent via the data socket.

I thought that this was a problem with Cerberus but I found that I had no problems when using WS-FTP client, IE (as a ftp client) or xplorer2. It appears that these programs send some sort of packet accross the connection every 60 seconds or so. I do have keep-alive enabled.

If I am downloading a series of small files I have no problem because data is being sent accross the control channel at the beggining of every new file.