January 04, 2014

Lab 23: OSPF Authentication

Configure OSPF on all routers. Let's configure MD5 authentication for OSPF between R1 and R2:

interface Serial0/0
 ip ospf authentication message-digest
 ip ospf message-digest-key 1 md5 TEST

As you see, OSPF MD5 authentication is enabled only on Serial0/0 interface of R2. So R2 and R3 are still OSPF neighbors with none authentication.

R2#show ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
3.3.3.3           0   FULL/  -        00:00:39    11.0.0.1        Serial0/1
1.1.1.1           0   FULL/  -        00:00:32    10.0.0.1        Serial0/0


R2#show ip ospf interface serial 0/0
Serial0/0 is up, line protocol is up
  Internet Address 10.0.0.2/24, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:05
  Supports Link-local Signaling (LLS)
  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 1.1.1.1
  Suppress hello for 0 neighbor(s)
  Message digest authentication enabled
    Youngest key id is 1


R2#show ip ospf interface serial 0/1
Serial0/1 is up, line protocol is up
  Internet Address 11.0.0.2/24, Area 0
  Process ID 1, Router ID 2.2.2.2, Network Type POINT_TO_POINT, Cost: 64
  Transmit Delay is 1 sec, State POINT_TO_POINT
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    oob-resync timeout 40
    Hello due in 00:00:01
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 4 msec, maximum is 4 msec
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 3.3.3.3
  Suppress hello for 0 neighbor(s)

# DOWNLOAD LAB 23 GNS3 FILE