| Verify RHEL 8 does not accept router advertisements on all IPv6 interfaces by default, unless the system is a router. |
Note: If IPv6 is disabled on the system, this requirement is not applicable.
Check to see if router advertisements are not accepted by default by using the following command:
$ sudo sysctl net.ipv6.conf.default.accept_ra
net.ipv6.conf.default.accept_ra = 0
If the "accept_ra" value is not "0" and is not documented with the Information System Security Officer (ISSO) as an operational requirement, this is a finding.
Check that the configuration files are present to enable this network parameter.
$ sudo grep -r net.ipv6.conf.default.accept_ra /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf /usr/lib/sysctl.d/*.conf /lib/sysctl.d/*.conf /etc/sysctl.conf /etc/sysctl.d/*.conf
/etc/sysctl.d/99-sysctl.conf: net.ipv6.conf.default.accept_ra = 0
If "net.ipv6.conf.default.accept_ra" is not set to "0", is missing or commented out, this is a finding.
If conflicting results are returned, this is a finding.