Once upon a time, Gordon Messmer gordon.messmer@gmail.com said:
DHCPv6 is really unusual. IPv6 addressing and routing is set up almost entirely in the kernel, unless you're using static addresses. IPv6 is neither harder nor easier with NetworkManager, in my experience.
Not sure about the version in CentOS, but in Fedora, NM disables kernel IPv6 autoconfiguration and "handles" it itself. This means that when I wake up my desktop from sleep, it can take 10-60 seconds to get working IPv6 (vs. the second or so it took the kernel). Progress...