After upgrading from FreeNAS 11 to TrueNAS 12, I noticed that my system date was incorrect. In examining it, I discovered that there is a set of ipfw rules in place:
root@nas:~ # ipfw list 00100 allow ip from any to any via lo0 00500 allow ip from table(internal) to any in 00500 allow ip from any to table(internal) out 01000 reject udp from any to me 111 01500 reject udp from me to any 65535 allow ip from any to any
This causes ntp to not work properly with the default servers. Or any servers not on the local network. I have been unable to figure out what is creating this. I have one plugin installed, Plex. The Plex jail has its own ipfw table, which is just to pass things through.
I also note that rule 1500 should probably be "reject udp from me to any 111"