Eric W. Biederman [off-list ref] wrote:
If loading the conntrack module changes the semantics of packet
processing when nothing is configured that is a bug in the conntrack
module.
Thats the default behaviour since forever.
modprobe nf_conntrack_ipv4 -- module_init registers netfilter hooks
and starts doing connection tracking.
You might say 'its wrong' but thats how its been for over a decade.
If you have a suggestion on how to transition to a 'sane' behaviour,
then I'm all ears.
Note however, that conntrack doesn't need any configuration currently.
Its just there once module is loaded.
We could try hooking into nftables/iptables modules that use conntrack
info to make a decision, and thats what we do now in namespaces other
than init_net.
We still do it be default in iniet_net because someone could be
doing conntrack just for purpose of ctnetlink events (conntrack -E and
friends, or flow accouting and the like).