package/gluon-wan-dnsmasq/files/lib/gluon/wan-dnsmasq/interface.d/050-gluon-wan-dnsmasq currently lists (netifd) interface names cellular_4 and cellular_6, but proto qmi interfaces only create an interface with _6 suffix when the dhcpv6 option is set - otherwise, IPv6 addresses (and presumably DNS servers) are found on the cellular interface itself.

This behavior was found using ifstatus on one of @maurerle's devices. It is likely sufficient to list cellular in the interface as well, but as the Telekom carrier does not provide any IPv6 DNS servers, no proper testing is possible on the device.

For consistency, cellular should also be listed for the wan firewall zone; here, the issue is only cosmetic, as the cellular_4 interface's ifname wwan0 is also picked up for ip6tables, even though there is no cellular_6 interface.

I can provide a PR, but I don't have any hardware to test on.

Gluon version: 8abad80 (main)

cc @blocktrron