📘 PCNSE OSPF Exam Essentials

1. OSPF Fundamentals

Protocol Type: OSPF is a link-state routing protocol that uses LSAs (Link-State Advertisements) to share routing information.
Area Types:
- Normal: Allows all types of LSAs.
- Stub: Blocks external LSAs (Type 5); can receive a default route from the ABR.
- Totally Stubby: Blocks external and inter-area LSAs (Type 3 and 5); only default route is advertised.
- NSSA (Not-So-Stubby Area): Allows external routes to be advertised into the OSPF domain as Type 7 LSAs, which are converted to Type 5 by the ABR.
Router ID: A unique identifier for each OSPF router, typically the highest IP address on the router or manually configured.
Cost: OSPF uses cost as its metric, calculated based on the bandwidth of the interface. Lower cost paths are preferred.

Navigate to Network > Virtual Routers and select the desired virtual router.
Under the OSPF tab, enable OSPF and configure the Router ID.
Define OSPF areas by adding Area IDs in x.x.x.x format and specifying the area type (Normal, Stub, NSSA).
Assign interfaces to OSPF areas and configure interface-specific settings such as cost and hello/dead intervals.
Configure redistribution profiles if integrating OSPF with other routing protocols or static routes.

For detailed configuration steps, refer to the official documentation: Configure OSPF – Palo Alto Networks

Understand the differences between OSPF area types and their use cases.
Be familiar with configuring OSPF on Palo Alto Networks firewalls, including area definitions and interface assignments.
Know how to redistribute routes between OSPF and other routing protocols or static routes.
Be able to interpret OSPF neighbor states and troubleshoot adjacency issues.
Understand how to use OSPF metrics and interface costs to influence routing decisions.