# OSPF: Neighbor 10.0.0.3 stuck in INIT state on interface GigabitEthernet0/1

- **ID:** `networking/ospf-neighbor-stuck-init`
- **Domain:** networking
- **Category:** routing
- **Verification:** ai_generated
- **Fix Rate:** 85%

## Root Cause

The OSPF router has received a Hello packet from the neighbor but the neighbor has not seen a Hello from this router, typically due to mismatched OSPF parameters (e.g., area ID, authentication, subnet mask) or a unidirectional link.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Cisco IOS 15.x-17.x | active | — | — |
| Juniper Junos 21.x-24.x | active | — | — |
| FRRouting 8.5-10.0 | active | — | — |
| Quagga 1.2-1.3 | active | — | — |
| Arista EOS 4.28-4.32 | active | — | — |

## Workarounds

1. **Verify OSPF configuration on both routers: `show ip ospf interface GigabitEthernet0/1` on Cisco to check area, network type, and authentication. Ensure both use the same area ID and authentication settings.** (85% success)
   ```
   Verify OSPF configuration on both routers: `show ip ospf interface GigabitEthernet0/1` on Cisco to check area, network type, and authentication. Ensure both use the same area ID and authentication settings.
   ```
2. **Check for mismatched subnet masks: both interfaces must be in the same subnet. Use `show running-config interface GigabitEthernet0/1` to compare.** (80% success)
   ```
   Check for mismatched subnet masks: both interfaces must be in the same subnet. Use `show running-config interface GigabitEthernet0/1` to compare.
   ```
3. **If using authentication, ensure the key and type match: on Cisco, `ip ospf message-digest-key 1 md5 <key>` on both sides.** (75% success)
   ```
   If using authentication, ensure the key and type match: on Cisco, `ip ospf message-digest-key 1 md5 <key>` on both sides.
   ```

## Dead Ends

- **Resetting the OSPF process without checking configuration mismatches** — The misconfiguration (e.g., area mismatch) persists, so the neighbor remains stuck in INIT after the reset. (90% fail)
- **Increasing OSPF hello/dead intervals on one side only** — Mismatched timers can cause the neighbor to stay in INIT or EXSTART; both sides must have consistent values. (80% fail)
- **Assuming the link is Layer 1 down and replacing cables** — The link is up (Hello received), but the issue is at Layer 3 (OSPF config); replacing hardware does not fix it. (70% fail)