Part 20 lab, Extended ACLs Configuration скачать в хорошем качестве

Part 20 lab, Extended ACLs Configuration

Access Control Lists (ACLs) are often taught as simple “permit or deny” rules. In reality, they control: • User traffic • NAT translations • Routing protocols • Management access In this lab, I demonstrated how ACL misconfiguration can silently break: OSPF adjacency Internet connectivity NAT functionality Topology highlights: • VLAN 10 (192.168.10.0/24) • VLAN 20 (192.168.20.0/24) • VLAN 30 (192.168.30.0/24) • PAT configured on edge router • OSPF between L3 switch and R1 Critical engineering insights: ✔ NAT changes source IP addresses ✔ ACLs evaluating private IPs must be applied BEFORE NAT ✔ OSPF uses IP protocol 89 (not TCP/UDP) ✔ ACL processing is top-down ✔ Extended ACLs provide precision and safety Packet flow order (often misunderstood): ACL check Routing decision NAT translation Exit interface One incorrect deny statement can disable routing without obvious errors. In modern infrastructure — on-prem, cloud, hybrid — ACL logic is foundational to: Cybersecurity strategy Zero-trust design Cloud networking Enterprise segmentation AI infrastructure environments Precision matters. Because networks don’t fail loudly. They fail silently. #CyberSecurity #Networking #CloudEngineering #Cisco #CCNA #NetworkSecurity #OSPF #NAT #ITInfrastructure #DigitalSecurity #AIInfrastructure #TechLeadership