IoT Needs Bi-Directional IPv6 In Mobile Networks

I’m probably one of the few people on this planet who appreciates and uses IPv6 both over my DSL connection at home and also over my cellular connection. Unfortunately there is one thing missing on the mobile side: Unrestricted incoming IPv6 access.

On both my fixed line and mobile connection I get a public IPv6 prefix assigned and things are good for outgoing connections. Incoming connections are also fine on my fixed line at home. By default my router blocks incoming IPv6 connection requests and only lets those through that I’ve configured on my router. On the mobile side however, the network blocks all incoming IPv6 connection requests. In other words it’s impossible to reach a server behind such a link via IPv6.

Obviously that protects ordinary users from unsolicited, unwanted and perhaps even malicious incoming connection requests. But like Network Address Translation (NAT) in IPv4, blocking incoming IPv6 connection requests results in a unidirectional Internet and prevents a lot of other uses. Especially for the Internet of Things (IoT) such a limitation is going to be a problem.

But some network operators show that one can have the best of both worlds. Take Austrian network operator “Drei” for example who by default, like everyone else, uses Network Address Translation but offers customers an easy way to get a public IP address that is reachable from the outside. I wished more operators would have already followed their example.