Cisco Cisco IOS Software Release 12.2(14)S

The benefits of migrating from the old method of clear text authentication to the new method of clear 
text authentication are as follows:

Passwords are easier to change and maintain.

Passwords can be encrypted when the system configuration is being displayed (if you use key 
management).

Before you can configure authentication, you must decide whether to configure authentication for the 
IS-IS instance or for individual IS-IS interfaces (both tasks are in this section).

To achieve a smooth transition to authenticating LSPs, perform the following steps in the order shown, 
which requires moving from router to router doing certain steps before all the steps are performed on 
any one router.

configure terminal 

key chain name-of-chain

key key-id

key-string text

router isis area-tag

authentication send-only [level-1 | level-2]

Repeat Steps 1 through 8 on each router that will communicate.

name-of-chain [level-1 | 

]

Router(config-if)# isis authentication key-chain 

multistate87723

Enables MD5 authentication for an IS-IS interface.

Refer to the key management feature, which is 
referenced in the “Related Documents” 
section.

Repeat Steps 10 and 11 on each router that will communicate. —

Router(config-if)# no isis authentication send-only 

Router(config-if)# no isis authentication send-only

Specifies that MD5 authentication is performed on 
packets being sent and received on a specified IS-IS 
interface.

Repeat Step13 on each router that will communicate.

—