IS-IS Authentication

1-) Clear text:

# router isis
# isis password MyPaSS

2-) Area password:

# router isis
# area-password YesAnAreaPass

3-) Domain password:

# router isis
# domain-password ThisWouldBeEasy

4-) MD5 Authentication:

Use it either under an interface or the whole router process; first create your key-chain. (Eg: keyISIS)

# interface s1/0
# isis authentication key-chain keyISIS
# isis authentication mode md5

or under router process

# router isis
# isis authentication key-chain keyISIS
# isis authentication mode md5

you can also limit it to level-1 or level-2 and send-only

# isis authentication mode md5 { level-1 | level-2 }
# isis authentication send-only { level-1 | level-2 }