Aborted Transfers
From BulletProof Wiki
During a file-transfer, either downloading, uploading or even directory listings; the control-connection is idle while the data-connection sends the information to/from the client to the server. It is *very* common for NAT/Firewalls to terminate idle connections after X seconds.
Since most people are running NAT/Firewalls, this idle-connection termination is most likely happening on both sides of the connection (at the server and at the client).
The most common way to combat this issue is to login to your NAT/Firewall and either increase the timeout or disable this feature. We will not be able to tell you specifically how to do this, as every firewall is different, but it should be well documented in your manual.
If you prefer not to change your firewall settings, we also recommend using our BulletProof FTP Client. The BPFTP client supports Firewall-KeepAlives. This is a NOOP (No-Operation) command sent over the control-connection to the server, keeping the connection alive by both NAT/Firewalls with traffic (Instructions Below). If you are not using BPFTP Client, you'll need to look into the documentation for your client. FYI: Web-Browsers, which can also be FTP Clients generally *do not* have this feature.
Turning on "Firewall Keep-Alives" in BPFTP Client:
- In BPFTP Client > v2.5x, this can be toggled under Tools -> Options -> Select "Operations" on the left and check the box labeled "Firewall Keep-Alive".
- In BPFTP Client <= v2.4x, this can be toggled under Options -> General Options -> Toggles and check the box labeled "Firewall keepalive".
Unfortunately there is not a 'keep alive' GUI feature on the BPFTP server software. However some MS windows server Operating Systems like 2003 have an alternate work around.
You will have to edit your registry to try to enable a keep alive on the TCP/IP via the operating system (we haven't tried this but the documentation on line seems to support this as a valid option... you are basically trying to have a keep alive packet sent prior to your firewall timing out)
Please review the following KeepAliveTime sections from one of these MS support links: Windows Server 2003 Win XP Win 2k
and also review the security update suggestion from following MS support article: http://support.microsoft.com/kb/831167
For more information on NAT/Firewalls, Control/Data Connections; please visit the following URL: http://bpftp.com/products/bpftpclient/windows/howto/firewall
If you are using Internet Explorer to download from your server, you can set also increase the default keep-alive time-out value in Internet Explorer
