pfSense

In a multiwan setup, when selecting only one listening interface (eg. LAN), NTPd does not select external peers as they are stuck init INIT, it does not seem to be a general connection issue:

[2.3.4-RELEASE]/root: ntpdate -q ptbtime1.ptb.de
server 192.53.103.108, stratum 1, offset 0.006594, delay 0.05330
21 Jul 13:28:45 ntpdate[18903]: adjust time server 192.53.103.108 offset 0.006594 sec
[2.3.4-RELEASE]/root: ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 ptbtime1.ptb.de .INIT.          16 u    -   64    0    0.000    0.000   0.000
 news01.nierle.c .INIT.          16 u    -   64    0    0.000    0.000   0.000
*presstore.int.m 192.53.103.108   2 u   45   64   17    0.148   -0.103   4.186

Note, presstore is an internal server.

When stetting ntpd to listen on multiple interfaces, external peers are selected again:

[2.3.4-RELEASE]/root: ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+hotel600.server 193.79.237.14    2 u   99  128  377   25.057   -2.118  30.495
+shattrath.sceen 193.190.230.66   2 u   91  128  377   25.750   -3.252  27.585
 presstore.int.m 162.23.41.55     2 u   21  128  377    0.142   -5.752   0.082
*ptbtime1.ptb.de .PTB.            1 u   27  128  377   30.631    1.814  24.172