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What is the TCP (and UDP) default window size on Windows Server 2008? I think it's 1480 bytes, but I'm not sure.

Can it be changed? How?

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up vote 3 down vote accepted

Part of Vista and Server 2008 is a next-generation TCP stack... it's auto-tuned, so there is no more TCPWindowSize tweak.

As far as changing it, you can turn auto-tuning on or off with these commands...

netsh int tcp set global autotuninglevel=normal
netsh int tcp set global autotuninglevel=disable
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Also note that the window size is not necessarily the same size as the MTU. It may be significantly larger - autotuning decides the best size for the network state.

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