@Mathias Dahl any thoughts on this FTP error?

Sorry, no. It's very hard to guess when it seems to be a random problem.

FTP uses two ports, one for the commands and one for the data. It sounds like the first one closes unexpectedly here.

Does it happen for all kinds of file sizes?

What firewall setup is in place between the application server and the FTP server? Any hints in logs there?

Hi @Mathias Dahl 

In my case it happens for all kind of file size and randomly. For example it may fail and in next try everything is ok.

During fails we have no information in FTP server logs and no network problem detected as well.

Do you have more than one node in the application server cluster? If you have and one of them have a connection problem, it could explain the randomness.

Hi @Mathias Dahl 

Customer environment is clustered. In ifsdump.zip file I have following servers list:

I realize that name is meaningless but I will ask customer for MainServer3. Thank You for hint.

Did you resolve the issue?

Hi @Mathias Dahl 

I have response from customer:

...it’s been working without issue since the Eater weekend – nothing was done in Live during that period…

I got also private message on IFS Community from another person:

Our customer also reported issue got resolved no clue what happened

Really strange!

Piotr

Perhaps a large consumption of easter eggs solved the problem?

I agree, it's strange. My guess is "connectivity". One thing is certain, the code didn't change, something external did (firewalls, caches, DNS stuff, OS processes, etc.)

Thanks for reporting back!

It could be related to Windows OS updates because in one of these two cases FTP is set on IIS. In second case I got only information that it also “windows FTP server software”.