# OSPF
### Base Setup
```
enable
config t
interface {interface} {interface_#}
no shutdown
ip address {ip_address} {subnet}
router ospf 1
network {network_address} {wildcard} area {area_#}
```
Example
```
enable
config t
interface GigabitEthernet 0/0
no shutdown
ip address 10.8.1.1 255.255.255.248
router ospf 1
network 10.8.1.0 0.0.0.7 area 0
```
### Add Authentication
#### MD5:
[Documentation](https://networklessons.com/ospf/how-to-configure-ospf-md5-authentication)
```
enable
config t
interface {interface} {interface #}
ip ospf message-digest-key {instance #} md5 {password}
ip ospf authentication message-digest
```
Example:
```
enable
config t
interface GigabitEthernet 0/0
ip ospf message-digest-key 1 md5 testing
ip ospf authentication message-digest
```
Verification:
```
enable
show ip ospf interface fastEthernet 0/0
```
Output:
Verification Output
#### SHA-512:
[Documentation](https://networklessons.com/cisco/ccie-routing-switching-written/ospf-hmac-sha-extended-authentication)
```
enable
config t
key chain {key_name}
key {#}
cryptographic-algorithm {algorithm}
key-string {password}
exit
interface {interface} {interface_#}
ip ospf authentication key-chain {key_name}
```
Example:
```
enable
config t
key chain R2
key 1
cryptographic-algorithm hmac-sha-512
key-string testing
exit
interface GigabitEthernet 0/1
ip ospf authentication key-chain R2
```
Verification:
```
enable
show ip ospf interface GigabitEthernet 0/1 | begin auth
```
Output:
Verification Output