FTP FileAdapter with "Active" Transfer Mode: Files are not recognized

[Former Member]

Dear All

Recently we established a new FTP FileAdapter channel which should pick WHSCON and POD messages from the external FTP share of our external logistics partner. The FTP server apparently allows only Active Transfer mode. The channel polls every 60 seconds.

The problem we are facing is that messages uploaded onto the FTP share by our partner are not recongized by the FTP channel. Only after restarting the channel the files are recognized and picked.

We are working on SAP-PI 7.0 (service pack 14).

QUESTIONS:

Does anybody share these problems with us?

Do you have any explanation for this nasty behaviour of the FTP channel?

Many thanks for sharing your experience with us.

Regards

Uwe

[JoelTrinidade · Accepted solution]

Hi Uwe,

I would begin by saying that When investigating an FTP problem, one of the first questions you should ask is whether active or passive mode is in use. ..... lifted from book Troubleshooting campus networks: page 587.

The problem that you are facing is because of the Active nature of your ftp . The drawback of the active nature is that The main problem with active mode FTP actually falls on the client side. The FTP client doesn't make the actual connection to the data port of the serverit simply tells the server what port it is listening on and the server connects back to the specified port on the client. From the client side firewall this appears to be an outside system initiating a connection to an internal clientsomething that is usually blocked.

These are just the beginning of the problems and one of them being files not getting recognized and picked. There are also problem relating to ftp handles . All this becomes very theoretical and its not a good idea to mention all over here.

Regards

joel

Edited by: joel trinidade on Jun 26, 2009 5:42 PM

[uwe_schieferstein · Accepted solution]

Hello Joel

Of course are your remarks useful and should be mentioned here.

Basically you express in technical terms what are my experiences with active and passive transfer mode when using FTP FileAdapter channels on SAP-XI.

I have asked our logistics partner whether they can change the settings of their FTP server in order to allow passive transfer mode.

Regards

Uwe

[uwe_schieferstein]

Dear All

As a workaround we scheduled a regular task which downloads the files from the remote FTP to a local directory on the SAP-XI server. Here the files are always recognized by the File channels.

Regards

Uwe