ISATAP router not sending RA messages on tunnel interface

[iacobansilviu1]

Hello,

I am trying to get my IPv4 only Windows 10 PC to connect to an IPv6 network using ISATAP. The IPv6 network is hosted in GNS3 and the PC is connected to it using the cloud node:

GNS3 Topology

In this topology, R3 plays the role of the ISATAP server. The communication between it and the PC client works just fine, as I can see the RS messages arriving on Gi0/2:

The problem is the router does not respond to these messages by sending RAs. RA messages are not suppressed:

Without these messages the client cannot assign to itself the global unicast address.

Any idea why this doesn't work as expected?

Thank you,

Silviu

 

[iacobansilviu1]

I have the same problem with 6rd tunnels. One of the routers doesn't send anything out the tunnel interface. I am using IOSv 15.9(3)M6.

[iacobansilviu1]

I have found the solution myself. ISATAP does not support multicast traffic so the router solicitation messages are unicast. So the router advertising messages will be solicited and unicast also. In CISCO IOSv 15.9(3)M6, the unicast solicited RA messages are not enabled by default and must be explicitely configured. The command is: ipv6 nd ra solicited unicast. Of course, the RAs at large must not be suppressed but I had already checked that.

With the 6rd the issue were related to the GUA IPv6 assigned addres at the remote site.

Everything working smoothely,

Cheers!