As a security best practice, verify that the host system denies IPv6 neighbor solicitations unless necessary. The dad_transmits setting determines how many neighbor solicitations are to be sent out per address including global and link-local, when you bring up an interface to ensure the desired address is unique on the network.

1

Run the # grep [01] /proc/sys/net/ipv6/conf/*/dad_transmits|egrep "default|all" command to verify whether the host system denies IPv6 neighbor solicitations.

2

If the values are not set to 0, configure the host system to deny IPv6 neighbor solicitations.

a

Open the /etc/sysctl.conf file.

b

If the values are not set to 0, add the following entries to the file or update the existing entries accordingly. Set the value to 0.

net.ipv6.conf.all.dad_transmits=0 
net.ipv6.conf.default.dad_transmits=0 
c

Save the changes and close the file.