I’ve been having these messages pop-up for a while when running tailscale:
# Health check:
# - Linux DNS config not ideal. /etc/resolv.conf overwritten. See https://tailscale.com/s/dns-fight
# - router: could not add magicsock port rule v6: adding [-p udp --dport 41641 -j ACCEPT] in filter/ts-input: running [/usr/sbin/ip6tables -t filter -A ts-input -p udp --dport 41641 -j ACCEPT --wait]: exit status 3: modprobe: FATAL: Module ip6_tables not found in directory /usr/lib/modules/6.8.7-1-default
ip6tables v1.8.10 (legacy): can't initialize ip6tables table `filter': Table does not exist (do you need to insmod?)
Perhaps ip6tables or your kernel needs to be upgraded.
The tailscale website recommends using systemd-resolved instead of NetworkManager so that it can rely on systemd and not rewriting resolv.conf constantly.
I don’t know anything about how openSUSE manages DNS.