What is OSPF Authentication? Configure OSPF with Authentication

By | 9th November 2015

OSPF Authentication (MD5).

 You can enable authentication in OSPF in order to exchange routing update information in a secure manner.
There are the three different types of authentication supported by OSPF:
Null Authentication—This is also called Type 0 and it means no authentication information is included in the packet header. It is the default.
Plain Text Authentication—This is also called Type 1 and it uses simple clear-text passwords.
MD5 Authentication—This is also called Type 2 and it uses MD5 cryptographic passwords.

RIPv2, EIGRP, OSPF, IS-IS, and BGP can all be configured to encrypt and authenticate their routing information.

This practice ensures that routers will only accept routing information from other routers that have been configured with the same password or authentication information.

Configure OSPF Authentication MD5

Use the following command for OSPF routing Authentication.

HQ#configure terminal

HQ(config)#interface Serial0

HQ(config-if)#ip ospf message-digest-key 1 md5 cisco


HQ(config)#router ospf 1

HQ(config-router)#area 0 authentication message-digest



 How to Configure OSPF Authentication MD5

 To enable OSPF MD5 authentication, you need to define the encryption key, which in essence is just a password on an interface. You must also permit authentication for the entire area. We use the network topology below for example:

Configure OSPF Authentication MD5.1

Also, you must permit OSPF authentication on other routers in the area, making sure that the authentication keys match on all interfaces that share the same network segment.

If you use authentication in an OSPF area, you must configure all of the routers in the area to support authentication. Every interface on a router doesn’t have to be configured with authentication.

But if you require authentication in any part of an area, you must include authentication support throughout the area.  The above example shows, the authentication of Area 0 with the following command:

HQ(config-router)#area 0 authentication message-digest

 Use the show ip ospf interface command to view the configured authentication on this interface.

Types of IPv6 Address

How to Configure IPv6 on Cisco Router.

How DHCPv6 Works

IPv6 Routing Protocols.

How to Configure IPv6 Static and Default Routes.

Host Standby Router Redundancy Protocol (HSRP)

Virtual Router Redundancy Protocol (VRRP)

Gateway Load Balancing Protocol (GLBP)

Spanning Tree Protocol (STP)

VLAN Trunking Protocol (VTP)

IPv6 Explained


RIPv6 or RIPng



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