使用 show ip ospf neighbor 命令 ，我們能發現相鄰狀態在"EXSTART"被滯留。
RTR-A#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 3.3.3.3 1 EXSTART/ - 00:00:37 3.3.3.3 Serial6/0:23 3.3.3.4 1 EXSTART/ - 00:00:39 3.3.3.4 Serial6/0:23 RTR-B#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 3.3.3.2 1 EXSTART/ - 00:00:36 3.3.3.2 BRI0 RTR-C#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 3.3.3.2 1 EXSTART/ - 00:00:35 3.3.3.2 BRI0
RTR-Bs配置顯示網絡類型點到點：
RTR-B#show ip ospf interface bri0 BRI0 is up, line protocol is up (spoofing) Internet Address 3.3.3.3/24, Area 2 Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_POINT, Cost: 1562 Transmit Delay is 1 sec, State POINT_TO_POINT, Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5 Hello due in 00:00:06 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 0 Suppress hello for 0 neighbor(s)
我們能使用debug ip ospf adj命令調試此 情況。請查看被采取的若 干示例輸出當在RTR-B運行此命令在以上時圖：
1: Send DBD to 3.3.3.2 on BRI0 seq 0xB41 opt 0x42 flag 0x7 len 32 2: Rcv DBD from 3.3.3.2 on BRI0 seq 0x1D06 opt 0x42 flag 0x7 len 32 mtu 1500 state EXSTART 3: First DBD and we are not SLAVE 4: Rcv DBD from 3.3.3.2 on BRI0 seq 0xB41 opt 0x42 flag 0x2 len 92 mtu 1500 state EXSTART 5: NBR Negotiation Done. We are the MASTER 6: Send DBD to 3.3.3.2 on BRI0 seq 0xB42 opt 0x42 flag 0x3 len 92 7: Database request to 3.3.3.2 8: sent LS REQ packet to 3.3.3.2, length 12 9: Rcv DBD from 3.3.3.2 on BRI0 seq 0x250 opt 0x42 flag 0x7 len 32 mtu 1500 state EXCHANGE 10: EXCHANGE - inconsistent in MASTER/SLAVE 11: Bad seq received from 3.3.3.2 on BRI0 12: Send DBD to 3.3.3.2 on BRI0 seq 0x2441 opt 0x42 flag 0x7 len 32 13: Rcv DBD from 3.3.3.2 on BRI0 seq 0x152C opt 0x42 flag 0x2 len 92 mtu 1500 state EXSTART 14: Unrecognized dbd for EXSTART 15: Rcv DBD from 3.3.3.2 on BRI0 seq 0xB42 opt 0x42 flag 0x0 len 32 mtu 1500 state EXSTART 16: Unrecognized dbd for EXSTART 第1行-第3行：RTR-B發送第一DBD到 3.3.3.2 (RTR-A)與順序0xB41并且從3.3.3.2接受第一DBD (RTR-A) 與順序# 0x1D06.鄰接協商仍然不完成。
RTR-B#show ip ospf interface bri0 BRI0 is up, line protocol is up (spoofing) Internet Address 3.3.3.3/24, Area 2> Process ID 1, Router ID 3.3.3.3, Network Type POINT_TO_MULTIPOINT, Cost: 1562 Transmit Delay is 1 sec, State POINT_TO_MULTIPOINT, Timer intervals configured, Hello 30, Dead 120, Wait 120, Retransmit 5 Hello due in 00:00:16 Index 1/1, flood queue length 0 Next 0x0(0)/0x0(0) Last flood scan length is 1, maximum is 1 Last flood scan time is 0 msec, maximum is 0 msec Neighbor Count is 1, Adjacent neighbor count is 1 Adjacent with neighbor 172.16.141.10 Suppress hello for 0 neighbor(s) RTR-B#show ip ospf neighbor Neighbor ID Pri State Dead Time Address Interface 172.16.141.10 1 FULL/ - 00:01:36 3.3.3.2 BRI0
