unbound generating too many log messages

[Philippe Meunier]

Hello,

I have a laptop computer running OpenBSD 5.8 configured to use unbound
version 1.5.4 and ntpd but which does not have any network interface
configured by default (except lo0, obviously) since which interface
needs to be configured and how depends on where I'm using the
computer.

After booting, unbound and ntpd both start without problem.  Then ntpd
automatically starts trying to contact NTP servers from pool.ntp.org,
which triggers DNS queries.  In turn unbound tries to contact root DNS
servers and fails since no network interface is configured yet.
Unbound then logs messages to syslog:

Jan 14 10:07:58 mycomputer unbound: [2824:0] notice: sendto failed: Can't assign requested address
Jan 14 10:07:58 mycomputer unbound: [2824:0] notice: remote address is 192.5.5.241 port 53

The problem is that unbound generates such a pair of messages up to 20
times for each root server!  That's 2 lines * 20 times * 13 root
servers = 520 lines that end up going to syslog.  Then 15 seconds
later ntpd tries again and you get another 520 lines, and so on.  This
continues until a network interface is configured.  The result is that
in three days I accumulated over 16000 lines of log messages like the
ones above...

For now I've simply disabled both unbound and ntpd at boot and
modified some scripts so that they are only started after a network
interface has been configured, but is there a way to make unbound more
quiet (short of sending the log messages to /dev/null)?
Or maybe change unbound's code to replace all those superfluous log
messages with a single "all DNS root servers are unreachable" message?

Thank you,

Philippe