[CentOS] Disabling IPv6 Auto Configuration

I am using stateless auto configuration for most of my clients. For
the servers I prefer to manually assign the address. I have defined
the IPv6 address in the ifcfg-eth0 file and set IPV6_AUTOCONF=no.
However ifconfig shows both the auto configured and manually assigned
address.

Looking around I found that net.ipv6.conf.default.accept_ra is set to
1 by default. The ifup-ipv6 is setting net.ipv6.conf.eth0.accept_ra to
0 like it should. From what I can tell the auto configuration is
happening right before net.ipv6.conf.eth0.accept_ra is set to 0. If I
define net.ipv6.conf.default.accept_ra = 0 in sysctl.conf
IPV6_AUTOCONF works as expected for both yes and no settings.

Has anybody else noticed this behavior?

Ryan