IPv6 ND Inspection

This topic is to discuss the following lesson:

Seems to be a typo:
“R1 and R2 are two legitimate devices with IPv6 addresses. I will use R3 to spoof an IPv6 address, SW1 is where we configure ND inspection.”

In the network diagram you have H1 and H2 instead of R1 and R2

Hello Elias

Thanks for pointing that out. I’ll let Rene know…


Hi Community !

I am finding most of the IPV6 first hop security topics (RAGUARD,DHCPGUARD,ND INSPECTION etc) NOT working with Cisco VIRL switch version as below.
Cisco IOS Software, vios_l2 Software (vios_l2-ADVENTERPRISEK9-M), Version 15.2(CML_NIGHTLY_20180619)FLO_DSGS7

This is a very important MUST PRACTICE topic on the ENARSI exam. please suggest suitable VIRL Cisco image.

Hello Raghu

You are correct. It seems that this particular switch version is behaving strangely. It has the ipv6 nd command available, but if you add anything after that, it says “unrecognized command.”

SW1(config)#inter gig 0/1

SW1(config-if)#ipv6 n?
nd  next-hop-self  

SW1(config-if)#ipv6 nd ?
% Unrecognized command
SW1(config-if)#ipv6 nd

Based on this Cisco learning network thread, others have faced similar situations. Still, others are able to implement RA Guard on this image. According to this documentation, it seems that IPv6 is not supported by this image (even though some of the commands appear!!):

One option is to use the NS-OX v which supports it. The commands are almost the same and the logic is the same. Alternatively, you can try downgrading to the previous IOSvL2 version as some threads state that this may resolve the issue.

Let us know how you get along!

I hope this has been helpful!


Hi Lazaros,

Could you please share the procedure to downgrade cisco Virl Cisco IOS Software, vios_l2 Software (vios_l2-ADVENTERPRISEK9-M), Version 15.2(CML_NIGHTLY_20180619)


Hello Raghu

Looking a little deeper, I see that someone using vIOS_L2 version 15.2(4.0.55)E was able to get the IPv6 nd ? commands to work. You can see this in the following Cisco learning network thread:


I suggest you go to the CML site where you can download the various vIOS versions available. But you will need a CML subscription to do so.

For detailed information about how to install the vIOS images, you will have to view Cisco’s CML support pages found here:

I hope this has been helpful!