iptables setting(syn_flood)

Limit the number of incoming tcp connections

Interface 0 incoming syn-flood protection

iptables -N syn_flood

iptables -A INPUT -p tcp --syn -j syn_flood

iptables -A syn_flood -m limit --limit 1/s --limit-burst 3 -j RETURN

iptables -A syn_flood -j DROP

#Limiting the incoming icmp ping request:

iptables -A INPUT -p icmp -m limit --limit  1/s --limit-burst 1 -j ACCEPT

iptables -A INPUT -p icmp -m limit --limit 1/s --limit-burst 1 -j LOG --log-prefix PING-DROP:

iptables -A INPUT -p icmp -j DROP

iptables -A OUTPUT -p icmp -j ACCEPT