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Background:

Currently trying to resolve the following:

  • IIS FTP server works after a fresh reboot for approx. 2-3 days.
  • After that, connecting to the FTP server is answered with an error (see below).
  • Restarting the FTP site within IIS Manager results in a hanging MMC.

The FTP connection attempt (via FileZilla) is answered with:

ECONNREFUSED - Connection refused by server

Other notes:

  • All other services like the side-by-side installed Apache server or the WWW part of the IIS work completely normally.
  • No (in my opinion) suitable/any entries in the event log.
  • No entries in the FTP log.
  • An IISRESET call from the command line works correctly, without any error (it does not resolve the FTP issue, though).

My questions are:

  • Any hints how to further find out in which "layer" this occurs (IIS, OS, HW, Xen)?
  • Is there any chance that this is caused by the Xen environment/drivers?

Of course, I also would like to hear ideas on how to resolve, if you have any.

Update 1:

As of request, I started netstat -ano | find ":21" on the server which results in:

TCP    217.160.24.234:21      212.87.131.182:52141   CLOSE_WAIT      1184
TCP    217.160.24.234:21      212.87.131.182:52146   CLOSE_WAIT      1184
TCP    217.160.24.234:21      212.87.131.182:52148   CLOSE_WAIT      1184
TCP    217.160.24.234:21      212.87.131.182:52149   CLOSE_WAIT      1184

217.160.24.234 is the IIS FTP server's public IP address, 212.87.131.182 is my local PC's public IP address (through our company gateway).

I'll now investigate further on how to interpret these results...

Running the same on a different webserver that has successful IIS FTP, these results look different:

TCP    0.0.0.0:21             0.0.0.0:0              LISTENING       1196
TCP    213.165.87.247:21      212.87.131.182:47746   ESTABLISHED     1196
TCP    [::]:21                [::]:0                 LISTENING       1196

Seems that my faulting server does not close the connections correctly?

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Uwe Keim
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    Is the service running when the symptom occurs? Does netstat reveal it is listening on port 21? – Greg Askew Jun 12 '13 at 10:02
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    FileZilla error is simply that it can't connect to your server meaning the service isn't running or working properly or possibly even a firewall blocking it. Check the event logs for messages about the FTP service as that will give you a better idea as to why the service is stopping if it is `crashing` or `being stopped`. Next time it happens check if the FTP service is running or stopped, and `netstat -ano | find ":21"` to see if its listening. – Brock Hensley Jun 12 '13 at 11:29
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    The FTP service is not listening on port 21. Did you confirm that the services is started in services.msc? – Greg Askew Jun 12 '13 at 14:07
  • Thanks, @GregAskew - Yes, I looked in Process Explorer seeing it running. A `net stop ftpsvc` runs forever, though. I'll think that one cause might be that I roughly transfer 20k files every night (backup) which might make the server run into some memory "overflow" thing. I'll try to replace IIS FTP with FileZilla Server to give it a try. – Uwe Keim Jun 12 '13 at 14:14

1 Answers1

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At first, I thought this was an issue with the IIS FTP service, so I "uninstalled"/deactivated it and installed FileZilla Server on the same system.

Turns out that the behaviour was not limited to FTP but also IIS HTTP.

Long story short:

I solved it by updating to the latest Citrix Tools for Virtual Machines.

Probably now I would be able to go back to IIS FTP but I'll stay with FileZilla Server since I'm rather happy with it.

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