MD5 OSPF on virtual-link

L’AUTENTICAZIONE  md5 sul VIRTUAL LINK  richiede

1)      Abilitazione md5 su tutte le interfacce nel percorso tra R16 e R18

2)      L’abilitazione sul Virtual ABR (R16) à  Area 0  Authentication message digest

R16

router ospf 2
 router-id 10.1.1.16
 log-adjacency-changes

:::::::::::::::::::::::::::::::::::::::::::::                  ç ADD    area 0 authentication message-digest                
 area 1 authentication message-digest
 area 3 authentication message-digest
 area 3 virtual-link 10.1.1.18 message-digest-key 1 md5 cisco
 network 1.1.50.0 0.0.0.3 area 1
 network 10.1.1.16 0.0.0.0 area 3
 network 172.16.13.0 0.0.0.7 area 3

 

R18

router ospf 2
 router-id 10.1.1.18
 log-adjacency-changes
 area 0 authentication message-digest

 area 3 authentication message-digest
 area 3 virtual-link 10.1.1.16 message-digest-key 1 md5 cisco
 redistribute static subnets
 network 1.1.60.0 0.0.0.3 area 3
 network 10.1.1.18 0.0.0.0 area 0
 network 10.10.20.0 0.0.0.7 area 0

TRA R16 ed R18 c’è un virtual link   (tra I due router c’è R17)

La neighbor sul virtual-link non si forma dal  debug si trova : MISMATCH Authentication type

mediante il comando SHOW IP OSPF VIRTUAL si capisce il perché à il virtual link e’ UP ma R18 usa MD5 (type2)  mentre  R16 usa nessuna autenticazione (type 0)

R18#sh ip osp virtual-links
Virtual Link OSPF_VL0 to router 10.1.1.16 is up  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 3, via interface Ethernet0/1
 Topology-MTID    Cost    Disabled     Shutdown      Topology Name
        0           20        no          no            Base
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:02
    Adjacency State FULL (Hello suppressed)
    Index 3/4, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, maximum is 0
    Last retransmission scan time is 0 msec, maximum is 0 msec  Message digest authentication enabled                     ß NON E’  PRESENTE SU R16
    Youngest key id is 1

R16#sh ip ospf virtual-links
Virtual Link OSPF_VL0 to router 10.1.1.18 is up  Run as demand circuit
  DoNotAge LSA allowed.
  Transit area 3, via interface Ethernet0/0
 Topology-MTID    Cost    Disabled     Shutdown      Topology Name
        0           20        no          no            Base
  Transmit Delay is 1 sec, State POINT_TO_POINT,
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:05
    Adjacency State FULL (Hello suppressed)
    Index 1/3, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, maximum is 0
    Last retransmission scan time is 0 msec, maximum is 0 msec

SOLUZIONE:

R16

router ospf 2

 area 0 authentication message-digest                 ß ADD