Command by command
| Cisco IOS | Linux | What it gives you |
|---|---|---|
show ip ospf neighbor | birdc show ospf neighbors | Adjacencies and their states |
show ip ospf interface | birdc show ospf interface | Per-interface OSPF settings |
show ip ospf database | birdc show ospf lsadb | Link-state database |
show ip route ospf | birdc show route protocol ospf1 | Routes learned via OSPF |
show ip protocols | birdc show protocols | Every protocol and whether it is up |
What the output looks like
$ birdc show ospf neighbors
BIRD 2.0.12 ready.
ospf1:
Router ID Pri State DTime Interface Router IP
10.0.12.2 1 Full/DR 00:17 ge1 10.0.12.2
10.0.13.2 1 Full/DR 00:16 ge2 10.0.13.2Why the two differ
On IOS, OSPF is part of the operating system, so one command shows both the protocol state and the resulting routes. On Linux there are two distinct layers. The daemon holds the link-state database, runs the SPF calculation and decides on best paths; the kernel holds only the routes the daemon chose to export. This is why a route can be perfectly correct inside BIRD and still absent from ip route show — an export filter blocked it. Checking both layers is the standard Linux routing workflow, and it has no IOS equivalent.
The trap
A neighbour stuck in Init means hellos are arriving in one direction only — the far side is not seeing yours. Stuck in ExStart most often means an MTU mismatch between the two interfaces, because OSPF exchanges database description packets sized to the interface MTU and refuses to proceed if they disagree. Both look like a generic "OSPF is not working" and have completely different causes.
Common questions
Why is birdc saying it cannot connect to the control socket?
The daemon is not running, or it exited on a config error. BIRD writes its control socket only after it has parsed the configuration successfully, so "connection refused" usually means a config problem rather than a networking one. Check the daemon's own log.
Does FRR use the same commands?
No. FRR deliberately implements IOS-style syntax, so on FRR you would run vtysh -c "show ip ospf neighbor" and get output close to Cisco's. BIRD uses its own vocabulary. Which one you use depends on which daemon is installed.
Stop reading, start running
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