Windows 7 network drops out when transferring files to SBS2003

George-Doble
George-Doble used Ask the Experts™
on
Setup:
Windows server 2003 small business server networked to 4 windows 7 PC's on a domain setup.

Problem:
When trying to transfer large files between the windows 7 machines and the server, half way through transferring the connection to the server drops out for up to 20 seconds before coming back on. needless to say the file transfer fails. I have disabled IPv6 from all the windows 7 machines and made sure the server and windows 7 machines are all up to date as well as trying a few things from other online forums but to no avail.

Additional information:
I took my windows vista laptop in today and put that on the network and it will transfer large files with no issues whatsoever so i am drawn to think it is the relationship between the windows 7 machines and server 2003.

The problems start occuring when trying to transfer a file about 1GB and over. it starts off transferring at a reasonable speed but between a quarter and half way through the network will drop out and the transfer fails.

Any help would be much appreciated!
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can you try and ping -t the server when the transfer is going on, and see wether the pc loses his connection entierly?

Author

Commented:
i have done that and basically it will drop out for about 4 packets saying request timed out and then come back on with a response time at about 900ms and sometimes it will drop out again for another 2 packets
ok and are you connecting on the hostname or IP?
are other pc's still able to access the server during these time-outs, just to check it's the pc and not server
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Author

Commented:
I ran a ping -t on all the computers back to the server and it timeouts on all of them. im connecting on the ip.
thanks for your help
this means the server loses it's network, and not the workstations.
Can you check the server's ram usage when you copy such a file.

I believe you are experiencing disk latency when transferring the files.
also try and disable tcp offloading on the server:

    [HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters]
make new dword (32)

name it "DisableTaskOffload" and set value to 1

check if problem persists after that, and if so, you can delete the key again or set to 0
David ChernyDirector

Commented:
I think setasoujiro is on the money. Disable offloading. You can do it form the command prompt (as an admin) with:

netsh int tcp set global chimney=disabled

Author

Commented:
I have tried the suggestion of disabling offload and still get the same result. i have pasted below a copy of the ping statistics when trying to transfer the file as i thought it might help.

Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Request timed out.
Request timed out.
Reply from 192.168.1.101: Destination host unreachable.
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Request timed out.
Request timed out.
Request timed out.
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128
Reply from 192.168.1.254: bytes=32 time<1ms TTL=128

As you can see the bit where it says destination host unreachable is the ip address of the computer not the server which seemed strange to me.

Any more help you can give is greatly appreciated
David ChernyDirector

Commented:
Hi George,

That error about your local PC not being able to reach the server is just a normal ping response (Reply from 192.168.1.101: Destination host unreachable) - it doesn't mean the PC was trying to ping itself, it just means that IP on the PC could not reach the target.

Are there any errors in the Windows 7 or Windows 2003 event logs, at the time of the drop outs?

Incidentally, does the Vista PC also drop pings? If so, I would suggest the NIC on the server is faulty.

If the Vista PC does not drop any packets during a ping test, try changing the Windows 7 NIC from auto sensing to fixed 100mbit full duplex (even if its a gb network) and retry the tests. If that drops nothing, try setting it to full duplex gb (if this applies in your network) and retry.

Let us know the results.

Commented:
I know that many will battle me on this here (it has been done before) but if you are not using IPv6 on the Windows 7 station then uncheck mark it in TCP/IP properties.  There is no need for it and it will sometimes try to take over by doing a broadcast to let everyone know that it is available (looking for a DHCP server that is running IPv6).
Thanks,
Kelly W.

Author

Commented:
The Vista machine also dropped packets during transfer but i tried changing both the windows 7 and server to 100mb/s to see if it made any difference but it still dropped packets. I then put it to 1gb/s and again it dropped packets. the only interesting thing that happened (im not sure if it helps or not) but the dropped packets came a lot later on in the transfer whereas when its on autodetect it comes a lot earlier.
Thanks
Director
Commented:
Given that. I'd say it's safe to assume the error is not the pcs. If everything drops packets to the server, the issue is either the server or your network. Try pinging pc to pc. If that drops packets too, it's your network. If not, it's your server and I would try a new nic on it.
LeeTutorretired
Top Expert 2009

Commented:
This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.

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