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Question:

How to avoid FTP download is cached

Jun 06 '16 at 11:58

Hello,

in some networks it happens that a downloaded file is cached somewhere. If later a new file but with same filename is downloaded, we receive the older file.

We are sure that this happens, since we check file size before (=on ftp server) and after download (=local file). And we're quite sure that it is a local network issue, as we have a few networks only where this happens. And at one network it happens since the server was changed from server 2003 to server 2012.

So I have two questions: - is it possible to connect and/or download a file and to insure that is the file from ftp and not a localy cached one? - which standrad component of a server 2012 does a ftp-caching and how to avoid this?

Thanks Florian


Answer

I've never heard of a caching issue with an FTP server. Caching typically involves HTTP. When an FTP client (such as Chilkat) connects to an FTP server, it's connecting directly to the FTP server. I don't see how any external caching mechanism could get in the way. It seems an impossibility to me..


Answer

Our workaround now is to rename file on ftp (by adding an unique id), to download it and to rename it back. Not nice but it works.

Florian


Answer

maybe it is a problem of configure of your sftp server??


Answer

Is it just missing the end records?

Take a look at the send and receive buffer sizes.


Answer

Is the source (client) getting a good return code?


Answer

Hello,

we found a WIN-API function DeleteUrlCacheEntry() but are not sure if this is in relation or helpful in our problem.

Florian


Answer

That function is to clear the cache. We have problems when something changes on the other end, and get failures to connect. We move that to another server to do the retries every 30 minutes 24x7. So we have to run ipconfig /flushdns twice a day, and then we get a success.

Microsoft has changed something in the registry which is causing your problem. They are always doing this. Look at the TCPIP section on both versions. I would also check that window size for send and receive buffers.


Answer

Hello

great- first time I see that someone has the same problem.

Microsoft has changed something in the registry which is causing your problem and do you know what exactly this is - or which settings are changed?

Look at the TCPIP section on both versions. What do you mean with 'on both versions' IPV4 and IPV6?

Florian


Answer

server 2003, server 2012.