Use a Raspberry Pi as an IPv6 bridge

Question

I want to configure a Raspberry Pi as a WiFi access point, as an IPv6-only network. My idea is to hook up an ethernet cable from an internet enabled existing network to the RPI, and use the RPI WLAN as an IPv6-only access point.

I will then connect Android devices to this new IPv6 network (an important part is that the new network must not give IPv4 addresses). I've read how to achieve this but I'm a little bit lost. It seems that I need to create a bridged network that bridges IPv6 and neither bridges nor routes IPv4.

Seems that net.ipv4.conf.all.forwarding or systemd.network IPForward can be configured, but I'm not sure how to set-up everything.

Thanks in advance!

Answer 1

In general, there are two ways to do that:

1) Routing: The WLAN segment and the LAN segment will be different, have different IP address ranges etc. The RaspPi will act as DCHP server and IPv6 prefix announcer. It routes (forwards packets) between LAN and WLAN.

2) Bridging: You bridge the WLAN AP interface and the LAN interface. There will be only one segment, it will have the same IP address range, and whatever controls your LAN with DHCP etc. will also control the WLAN. If you LAN has IPv4 addresses and you don't want them in the WLAN, you can use ebtables to filter them.

Which one do you want? Do find out which one do you want, can you elaborate why you need a IPv6-only network, and how your LAN is used? (IPv4/IPv6/both, etc.)?