Internet sharing with IPv6 only cellular modem and IPv4 wireless-lan hotspot

Product support balenaOS
1

Hello Support,

We are using iot-gate-imx8 in our product which needs to support internet sharing for wifi clients connecting to iot-gate-imx8’s wlan AP/hotspot. Please see below for our network setup.

Cell Internet <----> wwan0 CELL Modem (IPv6 global address) <—> wlan0 AP <-----> wifi clients (Android/IOS).

Recently, our ISP stopped issuing IPv4 address for cell modem connection and new defaults to IPv6 only. This resulted in wifi clients not able to access the internet. ISP doesn’t provide any IPv6 prefixes which can be delegated to wlan0 clients (NetworkManager[1245]: [1655222221.1842] policy: ipv6-pd: none of 0 prefixes of cdc-wdm0 can be shared on wlan0).

So we are looking for option to make internet sharing to work for wifi clients. Please see below for system-connections files for cell modem and wifi-hotspot.

cat /mnt/boot/system-connections/wifi-ap-1 
[connection]
id=wifi-ap
type=wifi
autoconnect=true
permissions=

[wifi]
band=bg
mac-address-blacklist=
mode=ap
ssid=<ssid>

[wifi-security]
auth-alg=open
key-mgmt=wpa-psk
psk=<shared-key-xxx>
group=ccmp
pairwise=ccmp

[ipv4]
dns-search=
method=shared
addresses=192.168.0.xx/24
never-default=true

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=shared

[proxy]


cat /mnt/boot/system-connections/modem-1 
[connection]
id=cellular
type=gsm
permissions=

[gsm]
apn=<APN>
auto-config=true

[ppp]
lcp-echo-failure=5
lcp-echo-interval=30

[ipv4]
dns-search=
method=auto
route-metric=1

[ipv6]
addr-gen-mode=stable-privacy
dns-search=
method=auto
route-metric=1

[proxy]


cat /etc/os-release 
ID="balena-os"
NAME="balenaOS"
VERSION="2.98.33"
VERSION_ID="2.98.33"
PRETTY_NAME="balenaOS 2.98.33"
MACHINE="iot-gate-imx8"
META_BALENA_VERSION="2.98.33"
BALENA_BOARD_REV=""
META_BALENA_REV=""
SLUG="iot-gate-imx8"
3

Hi there. Thanks for a clear description of the issue. To summarise - your Internet connection is IPv6 only and you’d like to share that to IPv4 clients on another interface, but the Internet connection doesn’t provide prefix delegation and the IPv4 clients aren’t able to access the shared connection. Did I get that right?

If so, I believe this might be a fundamental limitation of NetworkManager. Can you please review the following thread and let us know if it describes your situation? Then we can go from there.

5

Hello Hraftery,
Thank you for looking into this. Yeah, your summary is correct. And the thread you pointed describes the our situation.