Finally got the BizTalk FTP adapter running smooth and fast....(sigh)
At a customers site we use a BizTalk orchestration and dynamic send ports to deliver documents to a remote FTP site.
Everything worked without problems only the FTP deliveries were VERY slow....
It looked as if there was a gap of approximately 5 seconds between every FTP connection. And the delivery itself would take less
then a second. I tried almost everything to see if the problem was BizTalk related but as soon as I send the documents to another server, everything
was fast. So the problem was most liekly in the VPN connection.
Somebody wrote a small .Net FTP application that would mimic the BizTalk behaviour. And this test app was very fast as well.....
Finally I used the combination of Netmon to capture the frames and Etherreal to anylise the output to figure this one out.....
Screenshot of the Slow delivery :
As you can see BizTalk send a Quit command at 13:15:27, and the next connection made to the FTP Server was made at 13:15:31 (Titan FTP server xxyyzz Ready).
So between every send there was a time gap of approx 4 to 5 seconds.....
in between you see some yellow NBNS name queries that are the bottleneck. I really don't know what these NBNS queries are but I thought the BizTalk Server is trying to resolve
the IP address to a name, this doesn't succeed, so BizTalk tries again and fails again. Then BizTalk decided it cannot get this information and continues to send the data anyway.
( I guess BizTalk needs this data for reporting purposes somewhere. )
Once I obtained a MS-Certificate about MS-TCPIP (a long time ago) and remembered that a lot of name resolution stuff could be resolved by modifying the HOSTS file. So this is what i did.
I modified the host file of the BizTalk server and added the TCP/IP address and name of the Target FTP site.
Screenshot of the Fast delivery :
As you can see the QUIT is send at 13:56:36 and the new connection is set up at 13:56:36 (Titan FTP server xxyyzz Ready). So now there was no time gap inbetween two sends. And the
problem was solved. The FTP is now just as fast as on the local network.
I think it is strange that BizTalk will try to resolve the IP address to a host name regardless of the FTP adress entered. (The FTP Adress enetered is an IP adress).
Lotsa tools that do FTP don't show this strange behaviour. So if you experience the same problem of very low FTP trougput, have a look at netmon to see if you experience the