Thank you for your reply!
Perhaps your blog post is very helpful but it doesn't solve my problem.
Here is the result of executing the commands:
Code:
# iptables -A INPUT -i eth0 -p tcp --dport 5060 -m state --state NEW -m recent --setiptables: No chain/target/match by that name.
# iptables -I INPUT -p tcp --dport 22 -i eth0 -m state --state NEW -m recent --setiptables: No chain/target/match by that name.