正常的建鄰居過程：
失敗的建鄰居過程：
配置：
R1:
access-list 100 deny eigrp any any 華為裝置ACL不支援deny eigrp可以用協定号88代替
access-list 100 permit ip any any
interface serial 0
ip access-group 100 in
R2:
debug eigrp packets
在R2上會看到R2重傳16次後（重傳使用單點傳播），R2會重置鄰居。
建立鄰居表之前：
*Mar 1 00:09:43.467: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:09:43.467: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R2#
*Mar 1 00:09:47.235: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:09:47.239: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0
建立鄰居：
*Mar 1 00:10:07.647: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 12.0.0.1 (FastEthernet0/0) is up: new adjacency
*Mar 1 00:10:07.651: EIGRP: Enqueueing UPDATE on FastEthernet0/0 nbr 12.0.0.1 iidbQ un/rely 0/1 peerQ un/rely 0/0
R2#show ip eigrp neighbors
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 12.0.0.1 Fa0/0 11 00:01:02 46 276 0 6
建立鄰居異常：
R2#show ip eigrp neighbors
IP-EIGRP neighbors for process 100
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 12.0.0.1 Fa0/0 14 00:00:23 1 5000 2 0
SRTT 平滑往返時間 機關：（ms） 可靠封包發出到收到ACK的時間，正常越小越好
RTO 重傳逾時 機關：（ms） 給鄰居發送UPDATE封包，若鄰居未回複(未收到鄰居的ACK包)，則RTO時間過後再發。預設發16次，若16次鄰居都未确認，則重置鄰居。 注意：該時間是系統自行計算的，沒有預設值。（預設2000毫秒-3000毫秒-4500毫秒-5000毫秒-第4次至16次的重傳逾時的時間都為5000毫秒）
Q Cnt 隊列數量 0為正常 其他數字表示鄰居表建立有問題（排錯時注意檢視）
16次update包：
R2#
*Mar 1 00:10:09.667: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 1, RTO 3000
*Mar 1 00:10:09.671: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:12.011: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:12.011: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:12.483: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:12.487: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
*Mar 1 00:10:12.671: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 2, RTO 4500
*Mar 1 00:10:12.675: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:16.451: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:16.451: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:16.747: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:16.751: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
*Mar 1 00:10:17.175: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 3, RTO 5000
*Mar 1 00:10:17.175: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:21.167: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:21.167: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:21.675: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:21.675: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:22.179: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 4, RTO 5000
*Mar 1 00:10:22.183: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:25.447: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:25.447: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:26.315: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:26.315: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:27.183: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 5, RTO 5000
*Mar 1 00:10:27.187: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:29.987: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:29.987: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:30.863: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:30.863: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:32.187: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 6, RTO 5000
*Mar 1 00:10:32.191: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:34.651: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:34.651: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:35.447: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:35.451: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:37.191: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 7, RTO 5000
*Mar 1 00:10:37.195: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:38.939: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:38.939: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:39.767: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:39.771: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:42.195: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 8, RTO 5000
*Mar 1 00:10:42.199: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:43.723: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:43.723: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:44.351: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:44.355: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:47.199: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 9, RTO 5000
*Mar 1 00:10:47.203: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:48.287: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:48.287: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:10:48.791: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:48.791: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:52.203: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 10, RTO 5000
*Mar 1 00:10:52.207: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
*Mar 1 00:10:53.135: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:53.135: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R2#
*Mar 1 00:10:53.695: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:53.695: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:10:57.207: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 11, RTO 5000
*Mar 1 00:10:57.211: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
*Mar 1 00:10:58.039: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:10:58.039: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R2#
*Mar 1 00:10:58.351: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:10:58.351: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:02.211: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 12, RTO 5000
*Mar 1 00:11:02.215: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
*Mar 1 00:11:02.307: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:02.307: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:03.167: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:03.167: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:06.891: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:06.891: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:07.215: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 13, RTO 5000
*Mar 1 00:11:07.215: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:07.999: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:08.003: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:11.271: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:11.271: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:12.219: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 14, RTO 5000
*Mar 1 00:11:12.219: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:12.683: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:12.683: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:16.211: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:16.211: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:16.955: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:16.959: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:17.223: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 15, RTO 5000
*Mar 1 00:11:17.223: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:20.883: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:20.883: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:21.299: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:21.303: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:22.227: EIGRP: Sending UPDATE on FastEthernet0/0 nbr 12.0.0.1, retry 16, RTO 5000
*Mar 1 00:11:22.231: AS 100, Flags 0x1, Seq 4/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:25.479: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:25.479: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:25.915: EIGRP: Received HELLO on FastEthernet0/0 nbr 12.0.0.1
*Mar 1 00:11:25.915: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/rely 0/2
R2#
*Mar 1 00:11:27.231: EIGRP: Retransmission retry limit exceeded
*Mar 1 00:11:27.231: EIGRP: Sending HELLO on FastEthernet0/0
*Mar 1 00:11:27.231: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
*Mar 1 00:11:27.239: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 100: Neighbor 12.0.0.1 (FastEthernet0/0) is down: retry limit exceeded
R2#
*Mar 1 00:11:27.251: EIGRP: FastEthernet0/0 multicast flow blocking cleared