Optimizing Linux TCP/IP Networking
Some time ago I thought of ways to optimize my Linux Servers
network performanceand I googled around I found few interesting
websites which give me the idea of some of the basic sysctl
variables used for optimizing the GNU/Linux Network stack. Here are
the variables themselves and some good example values.
net.ipv4.ip_forward = 0 ( Turn off IP Forwarding )
net.ipv4.conf.default.rp_filter = 1 ( Control Source route verification )
net.ipv4.conf.default.accept_redirects = 0 ( Disable ICMP redirects ) *
net.ipv4.conf.all.accept_redirects = 0 ( same as above )
net.ipv4.conf.default.accept_source_route = 0 ( Disable IP source routing )
net.ipv4.conf.all.accept_source_route = 0 ( - || - )
net.ipv4.tcp_fin_timeout = 40 ( Decrease FIN timeout ) - Useful on busy/high load servers
net.ipv4.tcp_keepalive_time = 4000 ( keepalive tcp timeout )
net.core.rmem_default = 786426 - Receive memory stack size ( a good idea to increase it if your server receives big files )
net.ipv4.tcp_rmem = "4096 87380 4194304"
net.core.wmem_default = 8388608 ( Reserved Memory per connection )
net.core.wmem_max = 8388608
net.core.optmem_max = 40960 ( maximum amount of option memory buffers )
# like a homework investigate by yourself what the variables below stand for 
net.ipv4.tcp_max_tw_buckets = 360000
net.ipv4.tcp_reordering = 5
net.core.hot_list_length = 256
net.core.netdev_max_backlog = 1024
Hope this helps and gives you some idea of how network optimization
in Linux is usually done. Happy tweakening !