Which three conditions are required for two FortiGate devices to form an OSPF adjacency? (Choose three.)

Which three conditions are required for two FortiGate devices to form an OSPF adjacency? (Choose three.)
A . OSPF link costs match.
B . OSPF interface priority settings are unique
C . OSPF interface network types match
D . Authentication settings match.
E . OSPF router IDs are unique.

Answer: CDE

Explanation:

OSPF Interface Network Types:

The network types of the interfaces on both FortiGate devices must match. Common network types include broadcast, point-to-point, and non-broadcast multi-access (NBMA).

Authentication Settings:

Both devices must have matching authentication settings (if authentication is used). This includes the same authentication type (none, simple password, or MD5) and the same password or key.

OSPF Router IDs:

Each OSPF router must have a unique router ID within the OSPF domain. The router ID is typically an IPv4 address selected from one of the router’s interfaces or manually configured.

Link Costs and Interface Priority:

While link costs and interface priorities are important for route selection and designated router (DR) elections, they do not prevent OSPF adjacency formation if they differ.

Reference: Fortinet Network Security 7.2 Support Engineer Documentation OSPF Configuration Guides