Starting position: We send a request based on the IPv4 protocol to the DNS server of Google (8.8.8.8)

A request with the IPv4 protocol is based on a technology named as NAT, Network Address Translation. There are two variants of NAT:

The sender of a package is going to be changed by SNAT. The router will do this change, when he is going to send a package to the World Wide Web. He will use his own IPv4 address on the WAN interface as the Source Address, which is called masquerading. Thus, the destination device, DNS server of Google, knows where to reply to this request.

The router rembered the request which went out of him and he is going to send the answer of the DNS server to the end device by DNAT.


Let us imagine that I contact Google’s customer service to access one of my Smart Home devices, which is connected to my local network. The staff member is going to send an IPv6 request to the global IPv6 address of my device. The request will make a stop on my…


Let’s imagine that we call the IPv6 address of Google’s DNS server on the cmd console:

tracert [2001:4860:4860::8888]

The cmd console is working on my PC, which is connected with the router. The source address is the global IPv6 address of my PC and the destination address is the global IPv6 address of Google’s DNS server.

The request is going out of my router. Thus, he remembers the request. The next station of the IP package is the DNS server. The server addresses the packages to the router. The destination address is the global IPv6 address of my PC. The incoming packages to the router will be proved by its firewall. Due to the fact that the router remembered the request, its firewall will let the packages go to my PC. Now, I am able to call Google’s DNS server via IPv6.


When we connect a device to a router, the router will assign several IPv6 addresses to that device with different scopes. The most important scopes are named as link-local and global.

It is important to know that IPv6 addressess with a global scope only can be routed through the Internet…

Kerem Kenan

Homegrown IT-Administrator in Frankfurt

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