State Type not "None" still keeping state

[koehn]

I run an open NTP server on pfsense (it's part of ntppool.org). It receives several thousand queries per second over UDP, which results in a state table of 200,000 - 300,000 entries.

Since NTP has a 1-packet request and a 1-packet response, there's no need to use the state table for NTP as far as I can tell. On Linux servers we use iptables to disable conntrack for NTP.

I modified the firewall rule that allows NTP and set State Type to None. But after saving the changes and restarting the firewall, there's been no change in the state table.

Is there another setting I need to enable to avoid putting NTP into the state table?

I'm running 2.7.2-RELEASE (amd64).