BIND: Zone changes aren't immediately transferred to the secondary server

[Bagas Sanjaya]

Hi,

I noticed (possibly bug?) behavior from BIND on Ubuntu 22.04.

I'm running BIND on Ubuntu 22.04 LXD container inside my Debian laptop.

I have two container instances hosting BIND (mydns-ns1 as primary and
mydns-ns2 as secondary).

On primary, I configured zone file for testing zone (test.test), with
its reverse zone (10.99.99.0/24 aka 99.99.0.in-addr.arpa). The typical
zone file for testing zone consists of A records and PTR records (for
reverse zone), which for brevity I omitted from this post. I have set
$TTL and SOA Refresh at 86400 seconds.

To save a bit typing, I defined secondary servers on zone definition as:

    include "/etc/bind/secondaries";

with its contents as:

    allow-transfer {
        10.100.141.45; // secondary servers to be transferred to
    };

Similarly on secondary, I configured BIND to transfer from
primary. The corresponding include on zone definition is:

    include "/etc/bind/primaries";

with its contents as:

    primaries {
        10.100.141.245;
    };

After editing actual zone files for both testing and its reverse zone,
I reloaded named.service. The first transfer seems OK.

To test, I edit again both zone files (grammar fixing on testing zone
and simple serial bump on its reverse zone). I reloaded named.service
again, and I see only testing zone is transferred.

Then I do serial bump on both zones and reloaded named.service again.
This time neither zones are transferred. I had to force retransfer
by rndc retransfer.

Before force retransferring, I examined zone status for the reverse
zone on secondary, using rndc zonestatus, and I see:

    name: 99.99.10.in-addr.arpa
    type: secondary
    files: 10.99.99.db
    serial: 1
    nodes: 2
    last loaded: Tue, 03 May 2022 12:44:25 GMT
    next refresh: Wed, 04 May 2022 01:07:20 GMT
    ...

In this case, the zone will be transferred on less than 86400 seconds
(different from either $TTL or Refresh).

I expected that the transfer will be done in $TTL or Refresh time.

-- 
An old man doll... just what I always wanted! - Clara