When trying to receive a (large, approx. 100MB) file using an FTP adapter in BizTalk 2006, we run into the following problem, which causes the file to be processed over and over again.
- Retrieving the file succeeds; it is placed into the MessageBox and processed properly
- When the FTP adapter issues the DELE statement, it never reaches the FTP server the file is on (we have verified this by taking a look at the FTP server's logs)
- there are no signs of timeouts on the FTP server; the FTP server log does not mention a timeout occurring
- After the interval time set on the adapter expires, the FTP server will still find the large file that we have already processed in the previous run, because the DELE statement failed
The event log in BizTalk states that ‘The connection to the FTP server was broken prematurely’. That is why we think there is a timeout issue.
We have seen that retrieval of the file takes around 35 minutes. The FTP server timeout is set to 1 hour. no problems there I guess. Then we found the following article: http://www.ncftp.com/ncftpd/doc/misc/ftp_and_firewalls.html#FirewallTimeouts. It states that a firewall / routing device might be responsible for the timeouts. The team managing our firewalls and routers told us that there were no timeouts set here.
Which leaves us in the dark on the cause of our problem. Does anyone of you have any suggestions? Or even better, the solution!!