As a security best practice, verify that the host system denies the acceptance of router advertisements and Internet Control Message Protocol (ICMP) redirects unless necessary. A feature of IPv6 is how systems can configure their networking devices by automatically using information from the network. From a security perspective, it is preferable to manually set important configuration information rather than accepting it from the network in an unauthenticated way.
- Run the # grep  /proc/sys/net/ipv6/conf/*/accept_ra|egrep "default|all" command on the host system to verify whether the system denies the acceptance of router advertisements and ICMP redirects unless necessary.
- Configure the host system to deny IPv6 router advertisements.
- Open the /etc/sysctl.conf file.
- 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
- Save the changes and close the file.
# sysctl -pto apply the configuration.