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There are a few network parameters that can be tuned to better match
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There are a few network parameters that can be tuned to better match
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the kernel to your system hardware and intended usage. The defaults
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the kernel to your system hardware and intended usage. The defaults
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are usually a good choice for 99% of the people 99% of the time, but
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are usually a good choice for 99% of the people 99% of the time, but
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you should be aware they do exist and can be changed.
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you should be aware they do exist and can be changed.
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The current list of parameters can be found in the file:
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The current list of parameters can be found in the file:
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./linux/net/TUNABLE
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./linux/net/TUNABLE
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Some of these are accessible via the sysctl interface, and many more are
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Some of these are accessible via the sysctl interface, and many more are
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scheduled to be added in this way. For example, some parameters related
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scheduled to be added in this way. For example, some parameters related
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to Address Resolution Protocol (ARP) are very easily viewed and altered.
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to Address Resolution Protocol (ARP) are very easily viewed and altered.
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# cat /proc/sys/net/ipv4/arp_timeout
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# cat /proc/sys/net/ipv4/arp_timeout
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6000
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6000
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# echo 7000 > /proc/sys/net/ipv4/arp_timeout
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# echo 7000 > /proc/sys/net/ipv4/arp_timeout
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# cat /proc/sys/net/ipv4/arp_timeout
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# cat /proc/sys/net/ipv4/arp_timeout
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7000
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7000
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Others are already accessible via the related user space programs.
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Others are already accessible via the related user space programs.
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For example, MAX_WINDOW has a default of 32k which is a good choice for
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For example, MAX_WINDOW has a default of 32k which is a good choice for
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modern hardware, but if you have a slow (8 bit) ethercard and/or a slow
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modern hardware, but if you have a slow (8 bit) ethercard and/or a slow
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machine, then this will be far too big for the card to keep up with fast
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machine, then this will be far too big for the card to keep up with fast
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Tx'ing machines on the same net, resulting in overruns and receive errors.
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Tx'ing machines on the same net, resulting in overruns and receive errors.
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A value of about 4k would be more appropriate, which can be set via:
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A value of about 4k would be more appropriate, which can be set via:
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# route add -net 192.168.3.0 window 4096
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# route add -net 192.168.3.0 window 4096
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The remainder of these can only be presently changed by altering a #define
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The remainder of these can only be presently changed by altering a #define
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in the related header file. This means an edit and recompile cycle.
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in the related header file. This means an edit and recompile cycle.
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Paul Gortmaker 06/96
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Paul Gortmaker 06/96
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