Martin Gregorie  writes:
[...]
> ... where zappa.gregorie.lan physically the same hardware & software as
> localhost

I expect that it is a different IP address.

> Here's the behaviour I'm seeing:
>
> 1) setting 'host' to an undefined host name
>    (gets "Name or service not known" error)
>
> 2) setting it to a valid host name which is not running
>    ntpd (gets "read: Connection refused" if you try to query it)
>
> 3) setting it to a valid host name with ntpd running (gets
>    "***Request timed out" if you try to query it
>
> 4) setting it to 'localhost' (queries work OK).
>
> It doesn't seem to matter whether case 3 is the same system as in case 4,
> so there's evidently something amiss on the 'host' command, at least with
> version ntpq 4.2.8p13@1.3847-o Thu Mar  7 14:37:11 UTC 2019 (1)

You have a ‘restrict’ lines in /etc/ntp.conf permitting localhost to
query your ntpd but not other addresses.

--
https://www.greenend.org.uk/rjk/

--- SoupGate-Win32 v1.05