Scaling up number of tcp/ip connections in linux

#as client
sysctl net.ipv4.ip_local_port_range="20000 65535"
sysctl net.ipv4.tcp_fin_timeout=30

#as server
ifconfig eth0 txqueuelen 10000
sysctl net.core.somaxconn=10240
sysctl net.core.netdev_max_backlog=10000
sysctl net.ipv4.tcp_max_syn_backlog=2560
echo 3000000 > /proc/sys/fs/nr_open
ulimit -n 2000000