OSPF- Authentication

Case -1

Authentication type
Null     - No Authentication , This is a type
Plain text
MD5

Authentication is per interface base

Case -1 Plain-text  Authentication between R1-R3

R1 & R3 

router ospf 10
 area 0 authentication // Authentication enabled on area basis//

R1(config)#int fa0/1

R1(config-if)#ip ospf authentication-key cisco

%OSPF-5-ADJCHG: Process 10, Nbr 39.1.4.1 on FastEthernet0/1 from FULL to DOWN, Neighbor Down: Dead timer expired

R3#

%OSPF-5-ADJCHG: Process 10, Nbr 1.1.1.1 on FastEthernet0/0 from FULL to DOWN, Neighbor Down: Dead timer expired

R3(config)#int fa0/0

R3(config-if)#ip ospf authentication-key cisco

%OSPF-5-ADJCHG: Process 10, Nbr 1.1.1.1 on FastEthernet0/0 from LOADING to FULL, Loading Done

Case -1B Plain-text  Authentication between R1-R3

router ospf 10
 no area 0 authentication // Authentication disabled on area basis//

R1

%OSPF-5-ADJCHG: Process 10, Nbr 39.1.4.1 on FastEthernet0/1 from FULL to DOWN, Neighbor Down: Dead timer expired

R1(config)#int fa0/1

R1(config-if)#ip ospf authentication  // Authentication enabled on interface basis //

R1(config-if)#ip ospf authentication-key cisco

R3'

interface FastEthernet0/0

 ip ospf authentication

 ip ospf authentication-key cisco

in R1

FastEthernet0/1 is up, line protocol is up

  Internet Address 13.0.0.1/24, Area 0, Attached via Network Statement

  Process ID 10, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 10

  Topology-MTID    Cost    Disabled    Shutdown      Topology Name

        0           10        no          no            Base

  Transmit Delay is 1 sec, State BDR, Priority 1

  Designated Router (ID) 39.1.4.1, Interface address 13.0.0.3

  Backup Designated router (ID) 1.1.1.1, Interface address 13.0.0.1

  Flush timer for old DR LSA due in 00:01:44

  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

    oob-resync timeout 40

    Hello due in 00:00:08

  Supports Link-local Signaling (LLS)

  Cisco NSF helper support enabled

  IETF NSF helper support enabled

  Index 1/1, flood queue length 0

  Next 0x0(0)/0x0(0)

  Last flood scan length is 1, maximum is 4

  Last flood scan time is 0 msec, maximum is 4 msec

  Neighbor Count is 1, Adjacent neighbor count is 1

    Adjacent with neighbor 39.1.4.1  (Designated Router)

  Suppress hello for 0 neighbor(s)

  Simple password authentication enabled

Case -2        MD5 Authentication between R2-R5

in R2 & R5

key chain Test

 key 1

  key-string cisco

!

int  fa0/0

ip ospf authentication message-digest

ip ospf message-digest-key 1 md5 Test

sh ip ospf int fa0/0

FastEthernet0/0 is up, line protocol is up

  Internet Address 25.0.0.2/24, Area 0, Attached via Network Statement

  Process ID 10, Router ID 2.2.2.2, Network Type BROADCAST, Cost: 10

  Topology-MTID    Cost    Disabled    Shutdown      Topology Name

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

    Adjacent with neighbor 55.5.5.5  (Designated Router)

  Suppress hello for 0 neighbor(s)

  Message digest authentication enabled

    Youngest key id is 1

Case -2        MD5 Authentication between R2-R5 with multiple keys