networking routing ai_generated true

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

ID: networking/ospf-neighbor-stuck-init

Also available as: JSON · Markdown · 中文
85%Fix Rate
88%Confidence
1Evidence
2024-04-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
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 — — —

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.

generic

中文

OSPF路由器已收到邻居的Hello数据包，但邻居未看到此路由器的Hello，通常是由于OSPF参数不匹配（例如区域ID、认证、子网掩码）或单向链路。

Official Documentation

https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/13699-14.html

Workarounds

  1. 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. 
    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. 80% success Check for mismatched subnet masks: both interfaces must be in the same subnet. Use `show running-config interface GigabitEthernet0/1` to compare. 
    Check for mismatched subnet masks: both interfaces must be in the same subnet. Use `show running-config interface GigabitEthernet0/1` to compare.
  3. 75% success If using authentication, ensure the key and type match: on Cisco, `ip ospf message-digest-key 1 md5 <key>` on both sides. 
    If using authentication, ensure the key and type match: on Cisco, `ip ospf message-digest-key 1 md5 <key>` on both sides.

中文步骤

  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.
  2. 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.

Dead Ends

Common approaches that don't work:

  1. Resetting the OSPF process without checking configuration mismatches 90% fail

    The misconfiguration (e.g., area mismatch) persists, so the neighbor remains stuck in INIT after the reset.

  2. Increasing OSPF hello/dead intervals on one side only 80% fail

    Mismatched timers can cause the neighbor to stay in INIT or EXSTART; both sides must have consistent values.

  3. Assuming the link is Layer 1 down and replacing cables 70% fail

    The link is up (Hello received), but the issue is at Layer 3 (OSPF config); replacing hardware does not fix it.