said by dwk789:
So perhaps someone can answer a question I have always had about the IPv4/IPv6 transition. Can you not route between the two? How does that work? My thought is if the internet goes all IPv6 can't I still run a private IPv4 network on my side of my internet connection? Won't it continue to just work fine? That being the case do I really ever need IPv6 on my network or replace or upgrade my current equipment? I just ask this as I don't know these answers to these questions and maybe someone can explain how the routing between the two works?
It is possible, but very difficult to route between the two. Someone, somewhere has to operate a NAT64 service. Since some protocols have IP addresses embedded (fact, not going away, not intended to start a discussion about whether this is good or not), and IPV6 addresses are 4 times as long as IPV4 addresses, some protocols may not be translatable between IPV4 and IPV6.
The best means for the migration is dual stack. Dual stack is where the end point speaks IPV4 and IPV6 both, and can therefor speak to both IPV4 only and IPV6 only endpoints. It is possible to package IPV4 in an IPV6 packet to traverse a portion of IPV6 only network. It is also possible to package IPV6 in an IPV4 packet to traverse a section of IPV4 only network. It would be the responsibility of the last dual stack piece on either side of the IPVX only segment to do the packaging and unpackaging. These are called tunnels. Gogo6, Hurricane Electric, and a few others are tunnel brokers. One end of the tunnel is at their end and the other is on your network someplace.
As to security: IPV6 is not less secure than IPV4. Both of them require a firewall to be secure.