As stated in the 5.6.6 release notes, the default value of –bind-address has changed from IPv4-specific “0.0.0.0″ to “*” – the latter value which allows MySQL to bind to IPv6 interfaces by default. There are a few implications to this change.
First, make sure you’ve hardened both your IPv4 and your IPv6 access points to your MySQL server. If you are running IPv4 interfaces only, you can also change the –bind-address value back to the previous default value of “0.0.0.0″. Because MySQL now listens by default on both IPv4 and IPv6 interfaces, an installation that has only hardened IPv4 interfaces may find unaddressed vulnerabilities exposed via the IPv6 interface that is now used …
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