EIGRP Authentication

R2#sh run int fa0/0
interface FastEthernet0/0
 ip address 192.168.1.2 255.255.255.0
 ip authentication mode eigrp 1 md5
 ip authentication key-chain eigrp 1 2
end

R2#sh key chain 2
Key-chain 2:
    key 1 -- text "r2"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]
    key 2 -- text "r2"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]

R2#sh ip eigrp nei
IP-EIGRP neighbors for process 1
H   Address                 Interface       Hold Uptime   SRTT   RTO  Q  Seq
                                            (sec)         (ms)       Cnt Num
0   192.168.1.1             Fa0/0              5 00:00:15    1  5000  2  0
R2#
Nov  6 14:09:46.073: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 192.168.1.1 (FastEthernet0/0) is down: retry limit exceeded
Nov  6 14:09:46.893: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 192.168.1.1 (FastEthernet0/0) is up: new adjacency
R2#



R1#sh run int fa0/0
interface FastEthernet0/0
 ip address 192.168.1.1 255.255.255.0
 ip authentication mode eigrp 1 md5
 ip authentication key-chain eigrp 1 2
end

R1#sh key chain 2
Key-chain 2:
    key 2 -- text "r2"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]

R1#sh ip eig nei
IP-EIGRP neighbors for process 1
R1#

R1#deb eig pack
Nov  6 14:11:19.351: EIGRP: Sending HELLO on FastEthernet0/0
Nov  6 14:11:19.351:   AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R1#
Nov  6 14:11:20.603: EIGRP: pkt authentication key id = 1, key not defined or not live
Nov  6 14:11:20.607: EIGRP: FastEthernet0/0: ignored packet from 192.168.1.2, opcode = 5 (invalid authentication)
Nov  6 14:11:21.003: EIGRP: pkt authentication key id = 1, key not defined or not live
Nov  6 14:11:21.007: EIGRP: FastEthernet0/0: ignored packet from 192.168.1.2, opcode = 1 (invalid authentication)
Nov  6 14:11:21.207: EIGRP: Sending HELLO on FastEthernet0/0
Nov  6 14:11:21.207:   AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R1#u all
All possible debugging has been turned off


R2(config)#key chain 2
R2(config-keychain)#no key 1
R2(config-keychain)#end
R2#sh key ch
Nov  6 14:13:45.624: %SYS-5-CONFIG_I: Configured from console by console
R2#sh key chai 2
Key-chain 2:
    key 2 -- text "r2"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]
R2#

R1#
Nov  6 14:13:10.095: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 192.168.1.2 (FastEthernet0/0) is up: new adjacency
R1#

R2(config)#key ch 2
R2(config-keychain)#key 3
R2(config-keychain-key)#key-string r2
R2(config-keychain-key)#exit
R2(config-keychain)#no key 2
R2(config-keychain)#
Nov  6 14:20:16.747: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 192.168.1.1 (FastEthernet0/0) is down: Auth failure
R2(config-keychain)#do sh key ch 2
Key-chain 2:
    key 3 -- text "r2"
        accept lifetime (always valid) - (always valid) [valid now]
        send lifetime (always valid) - (always valid) [valid now]
R2(config-keychain)#

R1#
Nov  6 14:20:16.787: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 192.168.1.2 (FastEthernet0/0) is down: Auth failure
R1#deb eig pa
EIGRP Packets debugging is on
    (UPDATE, REQUEST, QUERY, REPLY, HELLO, IPXSAP, PROBE, ACK, STUB, SIAQUERY, SIAREPLY)
R1#
Nov  6 14:20:28.095: EIGRP: Sending HELLO on FastEthernet0/0
Nov  6 14:20:28.095:   AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R1#
Nov  6 14:20:30.007: EIGRP: pkt authentication key id = 3, key not defined or not live
Nov  6 14:20:30.011: EIGRP: FastEthernet0/0: ignored packet from 192.168.1.2, opcode = 5 (invalid authentication)
Nov  6 14:20:30.059: EIGRP: Sending HELLO on FastEthernet0/0
Nov  6 14:20:30.059:   AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R1#u all
All possible debugging has been turned off
R1#
Nov  6 14:20:31.927: EIGRP: Sending HELLO on FastEthernet0/0
Nov  6 14:20:31.927:   AS 1, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0
R1#