Unable to successfully ping IPv6 address

[User1527273]

Hello,

I am attempting to ping an IPv6 address for a router's G0/0/0 port and cannot get it successfully. The IPv6 ping for port G0/0/1 is OK as it is an IPv4 ping to port G0/0/0. 
I think that there might be an issue with the IPv6 address itself (2001:db8:acad:A::1/64), but I am not sure. I have ipv6 unicasting enabled and I have been pinging it without the prefix. 

Any help would really be appreciated, I am quite new at this and am struggling to troubleshoot it properly.

Thank you   

[Harold Ritter]

Hi @User1527273 ,

> The IPv6 ping for port G0/0/1 is OK as it is an IPv4 ping to port G0/0/0. 

I am not sure what you mean by that. Can you tell us a bit more on what that statement means?

> I think that there might be an issue with the IPv6 address itself (2001:db8:acad:A::1/64)

This address looks good. What is the address you are trying to ping?

Can you please provide the output for "show runn int gi0/0/0" and "show runn int gi0/0/1".

Regards,

[User1527273]

- I am getting successful ping's for other IP addresses for the same router, so I think it is something specific to that port or address .. maybe. 

- That's great, it is that IPv6 address that I have been trying to ping 
- When I attempt to put both of those commands in the CLI line it comes up with 'invalid input'. I have attached the output for 'show running config' if that is helpful. 

[Harold Ritter]

Hi @User1527273 ,

Thanks for the additional information. I didn't realize it was a Cisco Packet Tracer setup. 

What device is router1 interface gi0/0/0 connected to? Can you please attach the configuration for this device?

Regards,

[User1527273]

Oh sorry, I completely forgot to include that in my initial question. 
gi0/0/0 is connected to a pc - I've attached it's configuration down below. If it is easier I can attach the entire packet tracer file.

I really appreciate the help! 

[Harold Ritter]

Hi @User1527273 ,

The address on the PC is wrong. Devices sharing the same interface also need to share the same 64 bit prefix. The host IPv6 address needs to be 2001:db8:acad:a::125, which is the prefix configured on router1 gi0/0/0. You should be able to ping after that.

Regards,

[User1527273]

Thank you for your response, i changed the address for the PC, and that allowed me to ping router1 gi0/0/0. However, I needing to ping router1 gi0/0/0 from a different pc that is connected to gi0/0/0 via a switch and router 1 gi0/0/1. 
Given this, would it be best to change the address of router1 gi0/0/0? 
I've attached a screenshot of the topology and the configuration of PC-A, the switch and router 1 gi0/0/1 - I am currently trying to ping router 1 gi0/0/0 from PC-A and then PC-B from PC-A. 
Topology 

PCA config

switch config

router config

Really appreciate your time! 

[Harold Ritter]

Hi @User1527273 ,

You just need to set the IPv6 default gateway on PC-A and PC-B.

PC-A:

IPv6 default gateway: 2001:db8:acad:a::1

PC-B:

IPv6 default gateway: 2001:db8:acad::65

Regards,

[User1527273]

Unfortunatley, with the IPv6 default getway I am still getting an unsuccessful ping from PC-A to Router1 gi0/0/0. Would you have any other ideas why it could be? 

[Harold Ritter]

Hi @User1527273 ,

Please provide the configuration for both PC-A and PC-B. You could also zip your .pkt file and upload it here if you want.

Regards,

[User1527273]

Hi, 
I've just put my zipped file. 
And then I have the configurations for PC-A 

and PC - B

Thank you so much for all of your time! 

[Harold Ritter · Accepted solution]

Hi @User1527273 ,

You need to fix a few things to match what is configured on the router.

PC-A:

IPv6 gateway: 2001:db8:acad::65

PC-B:

IPv6 address: 2001:db8:acad:a::2

IPv6 gateway: 2001:db8:acad:a::1

You should then be able to ping from PC-A to PC-B end vice versa

Regards,

[User1527273]

Thank you so much! That has been a real help!

[Harold Ritter]

You are very welcome @User1527273 and thanks for the feedback