@dennypage said in NTP exposed to WAN by default:
specifying the listen by interface usually isn't necessary.
While I do agree here, I also think the ability to limit (when possible by the application/service) is a worth while security option to have. Should it be the number one priority - no prob not. And since pfsense is a firewall, you do have complete control of who can talk to what service that might be running no matter what the service does for binding to IPs the device might have.
I mean quite often many services would be on device with only 1 interface anyway ;) So the ability to call out what specific interface/ip a service is bound to really becomes moot. And it just makes it easier to setup to know that hey that service will listen to whatever IP the device has.
Back to the topic at hand, while ntp does out of the box listen on all IPs. Out of the box this would not be available via the wan no matter what IPs the service is actually listening on. Seems the OP clearly was not using valid testing methods (nmap to a udp port) - where nmap in layman terms reports I can't tell there was no answer.
What I don't get is how you could interpret
(not open|filtered)
To you got a ntp response. Or any response at all.
Nor did they follow up with validation of what they thought they were seeing before jumping to the conclusion that somehow pfsense left this service open to the wan even with default deny on all interfaces out of the box.. The only sort of exception to this is while the lan also has default deny, out of the box a any any rule is created to ease setup.