Score Higher on Verified 1z0-1124-25 | Oracle Cloud Infrastructure 2025 Networking Professional Exam Questions with Answers

Analyze Connectivity Successes:Instance A can ping its subnet gateway (10.0.1.1), indicating that local subnet routing and security rules are functioning for IPv4. It can also ping Instance B’s IPv6 address (fc00:1:2::20), confirming that IPv6 routing and security rules between subnets are operational.

Identify the Failure:Instance A cannot ping Instance B’s IPv4 address (10.0.2.20). Since security lists and NSGs allow all traffic, the issue is unlikely to be a security configuration problem.

Examine Routing for Instance A:The route table for Instance A’s subnet (10.0.1.0/24) has a rule directing traffic to 10.0.2.0/24 via the VCN Local Peering Gateway (LPG). In OCI, LPGs are used for intra-region VCN peering, but here, both instances are in the same VCN, so this rule is likely a misconfiguration or irrelevant unless peering is involved. However, the successful IPv6 ping suggests basic connectivity exists.

Check Return Path from Instance B:For a ping to succeed, Instance B must send ICMP replies back to Instance A (10.0.1.10). Instance B’s subnet (10.0.2.0/24) needs a route table entry to send traffic to 10.0.1.0/24. Without this, replies are dropped, causing the IPv4 ping to fail. The IPv6 success indicates that IPv6 routing is correctly configured both ways, possibly via SLAAC or default routes.

Evaluate Options:

A:Incorrect. IPv6 is enabled, as Instance A pings Instance B’s IPv6 address.

B:Correct. Missing route for 10.0.1.0/24 in Instance B’s subnet prevents IPv4 replies.

C:Incorrect. Security lists and NSGs can filter IPv6 traffic in OCI.

D:Incorrect. Ping supports IPv6, as evidenced by the successful IPv6 ping.

The most probable cause is a missing route in Instance B’s subnet route table. In OCI, each subnet has its own route table, and for instances in different subnets within the same VCN to communicate, both subnets must have appropriate routes. The successful IPv6 ping suggests that IPv6 routing is intact (likely due to default behavior or SLAAC), but IPv4 requires explicit routing. Per the Oracle Networking Professional study guide, "Route tables must be configured to direct traffic to the appropriate next hop for inter-subnet communication within a VCN" (OCI Networking Documentation, Section: Virtual Cloud Networks).

Goal: Apply least privilege for Cloud Shell to run diagnostics (ping, traceroute, nc) within a VCN.

Option A: Read permission on all virtual-network-family resources is too broad, granting unnecessary access beyond diagnostics—violates least privilege.

Option B: Instance Principals use temporary credentials tied to the Cloud Shell instance, enhancing security. A dynamic group with “read” and “use” permissions on NSGs and VNICs allows inspecting configurations and running diagnostics (e.g., via VNICs), meeting the exact need—correct.

Option C: Inspect permission only provides metadata access, insufficient for running diagnostics (e.g., no “use” for traffic)—incorrect.

Option D: Use permission on virtual-network-family at tenancy level is overly permissive, granting access to all network resources—violates least privilege.

Conclusion: Option B is the most restrictive and secure, aligning with least privilege.

Oracle states:

"Instance Principals allow services like Cloud Shell to authenticate without static credentials. Policies with ‘read’ and ‘use’ on specific resources (e.g., network-security-groups, vnics) enable diagnostics while adhering to least privilege."This supports Option B. Reference:Instance Principals - Oracle Help Center(docs.oracle.com/en-us/iaas/Content/Identity/Tasks/instanceprincipals.htm).

Objective:Efficiently propagate on-premises route updates to multiple VCNs.

DRG Capabilities:Supports route distribution to attached VCNs.

Analyze Options:

A:Manual updates are inefficient and error-prone; unsuitable.

B:Centralized DRG with route distribution automates propagation; efficient.

C:Multiple DRGs add complexity and manual effort; inefficient.

D:Service Gateway is for OCI services, not route updates; incorrect.

Conclusion:Centralized DRG with route distribution is the most efficient method.

Route distribution in a DRG simplifies multi-region routing. The Oracle Networking Professional study guide notes, "Using a centralized DRG with route distribution enabled allows routes learned from on-premises networks to be automatically propagated to all attached VCNs, reducing management overhead" (OCI Networking Documentation, Section: DRG Route Distribution). This leverages OCI’s automation capabilities.