Firewall

DDoS (Distributed Denial of Service) attacks are among the most common threats to cloud-native infrastructure and APIs. They can flood your services with traffic, exhausting resources and causing downtime. In this article, we’ll explore effective strategies to prevent and mitigate DDoS attacks — from rate limiting to cloud-based protections. 1. What Is a DDoS Attack? A DDoS attack occurs when a network of compromised machines sends overwhelming traffic to a target server or service, aiming to exhaust bandwidth or system resources. ...

Basic iptables Commands Every DevOps Engineer Should Know iptables is a powerful command-line utility for configuring the Linux kernel firewall. It is widely used for managing network traffic and securing Linux-based systems. Why Use iptables? Block unwanted traffic Allow specific ports Forward or redirect traffic Protect services from unauthorized access Basic iptables Syntax iptables -[A|D|I|R|L] [CHAIN] [OPTIONS] -A: Append a rule -D: Delete a rule -I: Insert a rule -R: Replace a rule -L: List rules Common Chains INPUT: Packets destined to the host OUTPUT: Packets sent from the host FORWARD: Packets routed through the host Examples List All Rules iptables -L -v -n Allow Incoming SSH (Port 22) iptables -A INPUT -p tcp --dport 22 -j ACCEPT Drop All Incoming Traffic By Default iptables -P INPUT DROP iptables -P FORWARD DROP iptables -P OUTPUT ACCEPT Allow Loopback and Established Connections iptables -A INPUT -i lo -j ACCEPT iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT Delete a Rule iptables -D INPUT -p tcp --dport 22 -j ACCEPT Saving and Restoring Rules Save Rules iptables-save > /etc/iptables/rules.v4 Restore Rules iptables-restore < /etc/iptables/rules.v4 Conclusion Understanding iptables helps you take full control over traffic flow in and out of your Linux systems. These basic commands will help you secure your infrastructure and troubleshoot network issues. ...