Configure the Message-Digest Authentication

Language:

Message-Digest authentication is a cryptographic authentication. A key (password) and key ID are configured on each router. The router uses an algorithm based on the OSPF packet, the key, and the key ID to generate a message digest that appends to the packet.

Configure the message-digest authentication in SEFOS2.
1. Type.
```
SEFOS# configure terminal
SEFOS(config)# interface vlan 1
```
2. Delete the authentication key for simple password authentication.
```
SEFOS(config-if)# no ip ospf authentication-key
```
3. Configure the authentication key for message-digest authentication.
```
SEFOS(config-if)# ip ospf message-digest-key 0 md5 asdf
```
4. Enable message-digest authentication.
```
SEFOS(config-if)# ip ospf authentication message-digest
```
5. Exit Interface Configuration mode.
```
SEFOS(config-if)# exit
```
6. Exit Configuration mode.
```
SEFOS(config)# exit
```

Configure the message-digest authentication in SEFOS4.
1. Type.
```
SEFOS# configure terminal
SEFOS(config)# interface vlan 1
```
2. Delete the authentication key for simple password authentication.
```
SEFOS(config-if)# no ip ospf authentication-key
```
3. Configure the authentication key for the message-digest authentication.
```
SEFOS(config-if)# ip ospf message-digest-key 0 md5 asdf
```
4. Enable message-digest authentication.
```
SEFOS(config-if)# ip ospf authentication message-digest
```
5. Exit Interface Configuration mode.
```
SEFOS(config-if)# exit
```
6. Exit Configuration mode.
```
SEFOS(config)# exit
```

Examine the configuration details in SEFOS2.

Examine the type of authentication configured.

SEFOS# show ip ospf interface
 
0
vlan1 is line protocol is up
Internet Address 10.4.0.2, Mask 255.255.0.0, Area 0.0.0.0
AS 1, Router ID 10.4.0.2, Network Type BROADCAST, Cost 1
Transmit Delay is 1 sec, State 5, Priority 1
Designated RouterId 10.4.0.4, Interface address 10.4.0.4
Backup Designated RouterId 10.4.0.2, Interface address 10.4.0.2
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Hello due in 0 sec
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with the neighbor 10.4.0.4
Message digest authentication enabled
Youngest key id is 0

Examine the adjacency formation between the neighbors.

SEFOS# show ip ospf neighbor detail
 
Neighbor 10.4.0.4, interface address 10.4.0.4
In the area 0.0.0.0 via interface vlan1
Neighbor priority is 1,  State is FULL/BACKUP, 5 state changes
DR is 10.4.0.4 BDR is 10.4.0.2
Options is 0x2