Ip – How does computer in IPv4 network communicate with computer in IPv6 network

ipipv4ipv6ipv6-transition

I have a Verizon cell modem that uses IPv6 addressing only. I can use it to access IPv4 addresses, like browsing the Internet. However, if I try to ping this IPv6 address on a cell modem from IPv4 network, it returns Destination host unreachable. Now I have two questions:

  1. Is it possible for a computer in an IPv4 network (including NAT,
    firewall, etc.) to access IPv6 addresses without too much tweaking? I
    tried to use a Teredo service. It seemed to worked for a time, and then
    I was not able to communicate with IPv6 addressing (for example,
    ipv6.google.com). Is there any tunneling service that I can use to
    bypass internal network layer and directly communicate with IPv6?
  2. If I want to open a service, say VNC service in computer connecting
    to that IPv6 cell modem, can I access this service from a regular
    IPv4 network?

Also, may I know where can I find knowledge regarding this kind of issues? It seems like I don't even have the right keywords to google.

Best Answer

IPv4 and IPv6 are two completely separate protocols, with separate, incompatible packet headers and addressing, and an IPv4-only host cannot directly communicate with an IPv6-only host.

The correct way to do this is to dual-stack one or both hosts so that they run both the IPv4 and IPv6 protocols. Otherwise, you must use some type of kludge to translate between IPv4 and IPv6, but there are problems and limitations with any of those. For example, there are far more IPv6 addresses than IPv4 addresses, so it is easier to translate an IPv4 address into something an IPv6-only host understands, than it is to do the opposite.

In 2017, the time has passed that there are still IPv4-only hosts and networks. Most ISPs support IPv6, and if your business has not yet begun to roll out IPv6, then it may find itself scrambling to do that in the future.

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