IS-IS Authentication

Lessons Discussion
1

This topic is to discuss the following lesson:

https://networklessons.com/cisco/ccie-routing-switching-written/is-is-authentication/

2

Thx Rene. Clear & Concise …

3

I tried the instance authentication but I keep seeing this message:

*Mar 1 00:07:13.255: %CLNS-4-AUTH_FAIL: ISIS: CSNP authentication failed

what could be missing in my configuration?

ip router isis
router isis
 net 49.0012.0000.0000.0001.00
 authentication mode md5
 authentication key-chain cisco@123
 log-adjacency-changes


interface FastEthernet0/0
 ip address 192.168.12.1 255.255.255.0
 ip router isis
 duplex auto
 speed auto
end
4

Hello Kacem

If you’re running this on GNS3 it could be an issue with the resources being allocated to dynamips. It has been known to create such error messages when the PC doesn’t have sufficient resources to provide for the emulator. This is especially the case when using MD5 as this takes up more resources.

Despite the error, is everything else working correctly? Are you getting a neighbor relationship and is the routing table being populated? If so, this seems to indicate that the issue is with resources.

If you’re sure your configs are correct, try to remove MD5 authentication and do clear text authentication and see if the error goes away.

I hope this has been helpful!

Laz