Tuning the Server

Increase ulimit

ulimit -n 65535

Increase the ports available

sysctl -w net.ipv4.ip_local_port_range="9000 65500"

And add this line to /etc/sysctl.conf

net.ipv4.ip_local_port_range=9000 65500

Increase max connections

sysctl -w net.core.somaxconn=324000

And add this line to /etc/sysctl.conf

net.core.somaxconn=324000

More limits

net.ipv4.tcp_max_syn_backlog=3240000

net.core.netdev_max_backlog=10000

net.ipv4.tcp_max_orphan=40000

Security limits

Add these lines to /etc/security/limits.conf

*               soft    nofile          65535
*               hard    nofile          65535