Granular Control: Security Lists offer granular control over inbound and outbound traffic. You can define rules specifying source IP addresses (VCN A IP range), destination IP addresses (resources in VCN B), and ports/protocols, allowing only authorized traffic to reach specific resources.
Direct Communication: Traffic flows directly between VCNs without intermediate hops, improving efficiency and performance.
Security Compliance: Security Lists align with the principle of least privilege, granting access only to necessary resources, enhancing security posture.
Comparison with other options:
DRG Route Rules (A): While possible, using DRG route rules for intra-VCN traffic becomes more complex and less manageable compared to Security Lists within VCNs.
NAT Gateways (C): NAT Gateways translate private IP addresses, but don,t provide control based on source IPs or security groups. They might introduce complexity and potential performance overhead.
Traffic Management (D): While Traffic Management can forward traffic based on source IPs, it,s primarily used for load balancing and complex routing scenarios. Security Lists offer a simpler and more direct solution for your specific requirement.