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If I have an IPv6 provided by my router via DHCP, and my router also has an IPv6, because there is no NAT involved with IPv6, does that mean that my computer is accessible directly from the internet? In otherwords, does this mean that my port 80 (if it is open) would be accessible from outside my firewall?

If that is not the case, how do I route traffic from IPv6 if there is no NAT (as I am reading it simply does not exist)?

billsecond
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  • Check to see in the Router Admin pages if it permits both IPv4 and IPv6. Most do. You can happily use IPv4 in a small network. I do that. If you wish, you can set your TCP/IP network settings on your computer to use IPv6 but I find it easier to use IPv4. My ISP modem externally used IPv6 but that does not mean we have to. – John Sep 11 '19 at 18:18

2 Answers2

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do not conflate routing, with firewalling. While NAT in ipv6 does exist, it's generally not needed. However just because a machine is routable (all the devices in the chain know how to get traffic to the destination) does not mean it is reachable (one of those devices could choose not to pass the traffic on).

So you need an ipv6 firewall, basically. If your home 'router' does this by default or not (i.e: it's actually a router/firewall device) we can't say without more information. You'd normally configure the v6 firewall the same way as the v4 one, - allow related and established traffic back in, and nothing else.

Sirex
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While with IPv4 you need to say that all traffic towards public-IP:public-port needs to be redirected to internal-IP:internal-port, with IPv6 your computer will have already a public IP that can be directly accessed from the internet.

One problem will be the router's firewall that by default will block such traffic. The computer's firewall may also be a problem.

Another problem will be the fact that the computer's IPv6 address as assigned by the ISP to your router will change from time to time, and with it the IPv6 address of all devices inside your local network.

To automatically solve this problem you need a dynamic DNS service such as the free dynv6.
See the article dynv6.com: IPv6 dynamic DNS done right.

harrymc
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