Packet tracer - autoconfig not working

[Lassek]

Hi

I created a small network with basic configuration on packet tracer to check how IPV6 address autoconfig works, however I'm unable to automatically obtain a  global unicast IP. I've searched on forums but so far no luck.

For this test I used only 2 2911 routers, A and B.

1. On router A I enabled IPV6 unicats-routing  and manually assigned an interface a global IPV6.

2 On router B I also enabled IPV6 unicats-routing and simply enabled (IPV6 enable) the interface linked to router A.

This automatically gave the interface the link local address, as expected.

Then I executed "IPV6 address autoconfig" which I expected to assign the global IP after a RA with the prefix was received. However, the interface doesn't get the global IP.

Using simulation mode I can see the RA ICMP packet type 134 being sent to router B with the correct prefix but the router doesn’t get a global IP.

This is the only configuration I’ve done on the routers.

Can anybody see what the problem is or where should I look to troubleshoot?

I've attached a screenshot with running config of both routers (i've removed some info)

Thansk in advance for any help

Raul

[Peter Paluch · Accepted solution]

Raul,

Perhaps the Packet Tracer is to blame - it often does not implement a particular functionality properly. From looking at your config, there seems to be nothing wrong with it. You could theoretically try to configure your RouterB without the ipv6 unicast-routing command, as that will cause it to revert to a host mode of operation. Perhaps the Packet Tracer wants you to do this. However, on real routers, you could safely have IPv6 routing turned on and yet have your interfaces auto-configured correctly.

Do you have an option of trying this on real IOSes? Perhaps GNS3 or VIRL, or real routers?

Best regards,
Peter

[Lassek]

Thanks Peter

Your hunch was correct. Disabling IPV6 did the trick and the interface got the global IP.

I don't think I would have ever guessed that disabling IPV6 was the solution.

Thanks again, you can't imagine how many hours I've wasted on this.

Regards,
Raul

[Peter Paluch]

Hi Raul,

You are very much welcome. Truth be told, I am also surprised that Packet Tracer wants you to deactivate IPv6 routing to allow a router to get its IP address via autoconfig.

Best regards,
Peter

[sasmanindeed]

i am using cisco packet tracer versiion 7.2, and the Auto connect is not working. when i click on it, it shows auto connect disable. what can is do?