Zone transfer is happening intermittently between slave and master bind

[Tony Finch]

Prasanna Mathivanan (pmathiva) via bind-users <bind-users at lists.isc.org> wrote:
>
> I couldn’t find anything from logs (checked both xfer and messages)

The best way to find out if a secondary server thinks a zone is
out-of-date is to look at the notify log messages. On the primary you'll
see something like

17-Mar-2021 12:36:28.311 notify: info: zone cam.ac.uk/IN:
	sending notifies (serial 1615984588)

and on a secondary you will see

17-Mar-2021 12:36:28.812 general: info: zone cam.ac.uk/IN/main:
	notify from 2001:630:212:8::d:aa#43432: serial 1615984588

followed by xfer-out (on the primary) and xfer-in (on the secondary). The
xfer messages tell you how much of the zone was transferred but not the
serial number.

or if the zone is in sync you will see

17-Mar-2021 12:20:36.985 general: info: zone cl.cam.ac.uk/IN/main:
	notify from 128.232.0.19#44340: zone is up to date

If the log messages do not match up like this then something isn't working
properly, such as the allow-notify ACL on the secondary - check there
aren't any erroneous "refused notify from..." messages in the secondary's
logs.

You can run `rndc notify` on the primary to trigger it on demand, which
can make debugging a bit more convenient. You can use `rndc zonestatus` on
the primary and secondary to see what they think the serial numbers are,
so you know whether the notify should trigger a transfer or not.

Tony.
-- 
f.anthony.n.finch  <dot at dotat.at>  https://dotat.at/
Wight, Portland, Plymouth: Northwest veering north or northeast, 3 to 5.
Slight or moderate. Mainly fair. Mainly good.