| 1 | <?xml version='1.0' encoding='UTF-8'?>
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| 2 | <!DOCTYPE topic PUBLIC "-//OASIS//DTD DITA Topic//EN" "topic.dtd">
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| 3 | <topic xml:lang="en-us" id="nat-adv-settings">
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| 4 | <title>Tuning TCP/IP Buffers for NAT</title>
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| 5 |
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| 6 | <body>
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| 7 | <p>The <ph conkeyref="vbox-conkeyref-phrases/product-name"/> NAT stack performance is often determined by its
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| 8 | interaction with the host's TCP/IP stack and the size of several buffers, <codeph>SO_RCVBUF</codeph> and
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| 9 | <codeph>SO_SNDBUF</codeph>. For certain setups users might want to adjust the buffer size for a better
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| 10 | performance. This can by achieved using the following commands, where values are in kilobytes and can range from 8
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| 11 | to 1024: </p>
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| 12 | <pre xml:space="preserve">$ VBoxManage modifyvm <varname>VM-name</varname> \
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| 13 | --natsettings1 16000,128,128,0,0</pre>
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| 14 | <p>This example illustrates tuning the NAT settings. The first parameter is the MTU, then the size of the socket's
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| 15 | send buffer and the size of the socket's receive buffer, the initial size of the TCP send window, and lastly the
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| 16 | initial size of the TCP receive window. Note that specifying zero means fallback to the default value. </p>
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| 17 | <p>Each of these buffers has a default size of 64KB and default MTU is 1500. </p>
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| 18 | </body>
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| 19 |
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| 20 | </topic>
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