1 2There are a few network parameters that can be tuned to better match 3the kernel to your system hardware and intended usage. The defaults 4are usually a good choice for 99% of the people 99% of the time, but 5you should be aware they do exist and can be changed. 6 7The current list of parameters can be found in the files: 8 9 linux/net/TUNABLE 10 Documentation/networking/ip-sysctl.txt 11 12Some of these are accessible via the sysctl interface, and many more are 13scheduled to be added in this way. For example, some parameters related 14to Address Resolution Protocol (ARP) are very easily viewed and altered. 15 16 # cat /proc/sys/net/ipv4/arp_timeout 17 6000 18 # echo 7000 > /proc/sys/net/ipv4/arp_timeout 19 # cat /proc/sys/net/ipv4/arp_timeout 20 7000 21 22Others are already accessible via the related user space programs. 23For example, MAX_WINDOW has a default of 32 k which is a good choice for 24modern hardware, but if you have a slow (8 bit) Ethernet card and/or a slow 25machine, then this will be far too big for the card to keep up with fast 26machines transmitting on the same net, resulting in overruns and receive errors. 27A value of about 4 k would be more appropriate, which can be set via: 28 29 # route add -net 192.168.3.0 window 4096 30 31The remainder of these can only be presently changed by altering a #define 32in the related header file. This means an edit and recompile cycle. 33 34 Paul Gortmaker 06/96 35