Passive Interface (OSPF)

A passive interface stops sending routing hellos on an interface while still advertising the network.

Updated: 2026-03-06

Definition

In OSPF, passive interfaces do not form neighbor adjacencies on that link, reducing risk and noise.

The network can still be advertised to other routers, depending on configuration.

Key points

No neighbor formation on that interface
Reduces attack surface and unnecessary traffic
Common on user-facing LAN interfaces

Common mistakes

Accidentally setting the wrong interface passive and breaking adjacencies.
Leaving routing hellos enabled on untrusted segments.

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