I recently had a client that was having issues downloading files and would disconnect after the 15 minute mark.
After reviewing our Filezilla server settings and checking the timeouts were all set correctly I began investing at what else could be causing this timeout. One of the things I noticed is that if you were downloading from a home computer or from a computer without a sophisticated firewall the download would not disconnect at the 15 minute mark and would complete the download successfully. I had a big hunch that this was because of some sort of policy on a client’s firewall.
Whether this is a Filezilla problem or a firewall issue is debatable. From what I understand FileZilla is creating a listening port on a separate connection, this separate connection is sometimes flagged as not in use and is dropped by some firewalls.
In order to fix this I applied settings on our side but these settings seem to need to be set on the client side the one “Downloading” the file.
In our Cisco Firewall I made the following modifications from the “Client Side” perspective in order to increase the time outs on specific port traffic. I had the client increase the timeouts on Ports 990 and 21. For ports 990 and 21 they created a service group and increased the time to 120 minutes. As soon as they did this, they were able to download the entire file as it took 24 minutes instead of 15 minutes.
I have applied the same settings to our firewall just in case of reverse transmission time issues
Cisco Firewall 5510/5525-X series