Denial of Service (DoS) Prevention

You can prevent DoS on you machine, by running following
commands as root user. Or you can put following lines
in a shell script and run it as root.

# shut some DoS stuff down
echo 1 > /proc/sys/net/ipv4/tcp_syncookies
echo 1 > /proc/sys/net/ipv4/icmp_ignore_bogus_error_responses
echo 1 > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

# increase the local port range
echo 1024 65535 > /proc/sys/net/ipv4/ip_local_port_range

# increase the SYN backlog queue
echo 2048 > /proc/sys/net/ipv4/tcp_max_syn_backlog

echo 0 > /proc/sys/net/ipv4/tcp_sack
echo 0 > /proc/sys/net/ipv4/tcp_timestamps