[CentOS] ICMPv6 Neighbour Solication request is not answered by linux when IPv6 address is assigned via Netlink code.

Tue May 21 06:10:06 UTC 2013
Kevin Peterson <qh.resu01 at gmail.com>

Hi, 

I have a process which is running as a linux service and assigns IP addresses using netlink to configued interface in linux.
For IPv4 addresses i do not see any issue with this assignment.

When i try to assign an IPv6 address, the address gets assigned successfully to the interface, but the Neighbour Solication request received for that address is not responded with and hence ping6 from a different machine doesn't work.

When i take the same netlink code and run it in a sample program the address gets assigned and the Neighbour solicitation is responded with a advertisement and hence ping6 works.

IP assigned by the program : 7000::15/32
IP on client machine from where ping6 is done : 7000::17/32.

Bot machines are connected to same Layer-2 switch.

I have flushed the ip6tables on both the machines just to rule out any firewall issues.

Thanks,
Kevin Peterson