Network Stalls/Freezes

What a nightmare. Can anyone help please?

We have a 50 user windows network that seems to stall as and when it feels like it.
Copying files can be superfast but other times the entire network stops

We have newly replaced 2x Netgear GS748TS Stacked switches
newly replaced all CAT5e Patch Leads
We have had the network infrastructure tested with a wavetek Tester and all issues repaired
New iscsi replaced Storage Solution with new Host running Server2008 r2

We have a mixture of Win7 Pro 64bit and XP Pro 64bit

We have applied all Windows updates to all the PC's inc Antivirus scans and spyware scans.

We have run wireshark and captured info but to be honest I am really struggling to understand the results.
I have microsoft Business Critical looking into it today but havent really progressed much.

Anyone have any ideas or possibly know a specialist?


smd333Asked:
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Matt VCommented:
When the network is slow, is everything slow or just certain things?  For instance, are file copies still fast but accessing network shares is slow?
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smd333Author Commented:
Reading and Writing can be hanging the network. Many users with spinning wheel but i can rdp onto the file storage server and navigate through the folders with ease on the same network.
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Matt VCommented:
When you RDP is it by IP or hostname?  What I am getting at is your DNS configuration.  Do all the clients point to the DC for DNS and only the DC?  And is your DNS running correctly.

Once of the quickest ways to halt an AD domain structure is with DNS issues.
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smd333Author Commented:
No. I am connecting to the actual server name.
I thought DNS so I have already cleaned it up. e.g. removed old computer accounts etc

The Microsoft dude didnt want to look at the DC which is the dns server as he thinks the problem is more related to the actual network traffic

Dns does appear to be working fine.

The Network Monitor tools that Microsoft use have detected packets not being approved and other errors that I have no idea about
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smd333Author Commented:
Sorry forgot to mention
If i copy data between servers. Super fast 1.5gb 7 secs
The servers are all plugged into the same switches as per the workstation
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Matt VCommented:
Do you have 801.x authentication enabled but not configured by any chance?
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smd333Author Commented:
Not sure about 801.x Authentication
Is this a feature in XP?

Definately not enabled on our Server 2008 Boxes
Unfortunately cannot check all the win7 PC's at the moment as they are off

Why do you ask?
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smd333Author Commented:
Logged onto a Win7 Pro 64bit PC 801.x Auth definately disabled
1gb File wants to take 8 hours of this machine to the Data store
Yet I can copy the same file from Server to Server in 7 secs without a blip
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Matt VCommented:
I was wondering if there was some sort of pause while it tried to authenticate.

The PCs and servers are all plugged into the same switch?

If some PCs are in one switch and some in another, do you see the same problem copying on the switch where the servers are versus the other switch?
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smd333Author Commented:
Sorry for the delay ref feedback
I have now done the following
I have been monitoring using wireshark
I discovered loads of ipv6 traffic that wasnt actually doing anything.
I have disabled this on the server 2008 and the win7 boxes.
I replaced a dodgy patch lead that had been trapped under a desk.
I disabled all extrenal access to the firewall accept port 443 and 25
We have had 2 days of good network performance now
I am still monitoring the packets to see if i see anything else worth investigating.
Microsoft are still analysing the logs so will see what happens in the new year with this case.

Naturally disabling ipv6 is not a permanent fix and will need fixing. But for now a result.


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Network Management

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