zone refresh timeout

[Stephane]

Hello,

I currently have 2 dns servers running, slave and master, holding the
same domains zones, which have 2 NS defined as this 2 servers.

I now want to set up a third nameserver. I configured it and it is
running, answering to dig queries.
It holds the same zones as my slave nameserver.
But it can't refresh the zones it holds, as shown in the logs:
general: info: zone exple.com/IN: refresh: failure trying master
81.28.111.11#53: timed out

If i define this new nameserver as a NS in a domain zone, the zone is
well refreshed.
So my question is, am I forced to declare this new nameserver as a NS
in each zone on the primary in order to have this zone refreshed on
the new dns server?
can't i just get a refreshed copy of the zone when it's ttl has
arrived?
I've watched the configuration, but didn't find a way to do that... so
i ask...

thanks,
Stephane