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Server 2008 R2 poor network speeds

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Last Modified: 2012-05-11
I have a Server 2008 R2 server that is getting poor network speeds. I am getting 70 Mbits per second on a Gigabit connection. I have looked at all the settings on the switch for duplex and speed and eveything is correct. There are no errors reported on the port.

I have also installed a new NIC, going from a Broadcom to an Intel NIC, with no change.

I imagine now that it has to be something with the OS, but I am not sure what it could be.

Any ideas on what could be holding back the speed in the OS?
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We have experienced the same issue on all our 2008 R2 machines.  We now run this command standard:

Open cmd prompt as Admin:

netsh interface tcp set global autotuninglevel=disabled

Disable autotuning feature completely and fit and lock the RWIN receive window to default value 65536 bytes.

To re-enable:

netsh interface tcp set global autotuninglevel=normal

Try running it and testing, if it doesn't help you can re-enable.
SouljaSr.Net.Eng
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Top Expert 2011

Commented:
Are you sure you are looking at 70 MB/sec instead of Mbit/sec. I know file transfer rate is usually measure in MB/sec. Thus 70MB/sec would translate to 560Mbits/sec out of the 1000Mbit/1Gig connection.
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Author

Commented:
it is 70 Mbits per second.
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Commented:
Do you have an anti-virus or firewall program that inspects packets? If you can, try disabling any firewall and anti-virus on the machine. Products like Symantec and a few others inspect each network packet, but it can only run so fast and ends up limiting the network speed.
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Author

Commented:
Disabling the autotuning helped a little bit, went from 70 to 100 mbits/sec, but still not what I am looking for. However this makes me think even more that it is a OS related issue.
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Author

Commented:
I stripped all antivirus and firewalls off of the server for testing purposes.
Are you using NIC teaming  at all?

Is the 70Mbps inbound our outbound (or both).  

You could take a look at RSS (Receive Side Scaling) sometimes disabling this can help as well.
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Author

Commented:
by the way, I am using iperf for testing. I have been using tcp for testing purposes. I just tested udp and the performance in 1Mbit per second!!

Some more information:

When I use iperf on the troubled server and run it as both the client (using the server IP address) and server i get the same bad speeds.

However if I browse through SMB from the server to itself, I get the speeds that I should be getting.


@sharkbot
it is both ways.

I disabled RSS with no effect




Here are the tcp global settings

TCP Global Parameters
----------------------------------------------
Receive-Side Scaling State          : disabled
Chimney Offload State               : automatic
NetDMA State                        : enabled
Direct Cache Acess (DCA)            : disabled
Receive Window Auto-Tuning Level    : disabled
Add-On Congestion Control Provider  : ctcp
ECN Capability                      : disabled
RFC 1323 Timestamps                 : disabled
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Author

Commented:
One additional thing to note, when copying a file using explorer, I am getting a transfer speed of 15-20 MBytes per second(better but not great). Every application installed on the server is getting about a 1/3 of that.
Are you by chance using Symantec Endpoint?
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Author

Commented:
I was using Symantec Endpoint. I was just looking at the teefer2 drivers.
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Author

Commented:
I should clarify and say that I has SEP installed. I removed it for testing but it seems to have left teefer2 mini drivers behind, which of course cant just be uninstalled. I was able to remove the teefer2 driver for the network adapters, but there is still an IP, IP6, and WAN device left behind, although they are disabled.
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Author

Commented:
I ran symantec clean sweep on the server and removed teefer2 driver. It had no effect.
I think we ended up redoing our server from scratch, the uninstall still left behind a ton of reg entries and stuff.  Trying to find my change logs sorry for the delay
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Author

Commented:
No problem, I am just about at that point. The only thing that is on the server is netbackup, so it won't be to hard to rebuild it, except that the server is in china.
We actually uninstalled then reinstalled with the patch.  That made operation normal then we uninstalled again.  If was a patch issue
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Author

Commented:
Do you know what the patch is?
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Author

Commented:
Hmmmm....

I am acutally in the process of uninstalling it now. I downloaded that version from Symantec this morning and installed it. Now I get speeds of 20 Mbits/second.
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Author

Commented:
After the install of SEP there was no change. Additionally I reset the tcp ip stack and that had no effect.

I went through and uninstalled all other applications and stopped all services that were not absolutely essential and there was no change.

I am planning on reinstalling this machine.
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Commented:
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Commented:
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