Recently see lots of attacks. Try to protect the system. Currently using iptables and fail2ban. It is not enough. I see the following page explain rate limit.
# Trixter's SIP rate limiter (This helps protect you from DoS attacks)
iptables -A INPUT -p udp --dport 5060 -m limit --limit 5/s --limit-burst 5 -i eth0 -j REJECT
iptables -A INPUT -p udp --dport 5080 -m limit --limit 5/s --limit-burst 5 -i eth0 -j REJECT
What is the best limit for 500 phones. Is there any other best practice to protect the system for Dos attacks.
Thanks
Lloyd