timeout retrying without EDNS master

[Emil Natan]

Hi list,
Follows part of the named log that I do not fully understand so any help
will be well appreciated:

Oct 21 15:52:58 nstest1 named[15684]: general: debug 1: zone_timer: zone
superfly.org/IN: enter
Oct 21 15:52:58 nstest1 named[15684]: general: debug 1: zone_maintenance:
zone superfly.org/IN: enter
Oct 21 15:52:58 nstest1 named[15684]: general: debug 1: queue_soa_query:
zone superfly.org/IN: enter
Oct 21 15:52:58 nstest1 named[15684]: general: debug 1: soa_query: zone
superfly.org/IN: enter
Oct 21 15:53:43 nstest1 named[15684]: general: debug 1: refresh_callback:
zone superfly.org/IN: enter
Oct 21 15:53:43 nstest1 named[15684]: general: debug 1: zone superfly.org/IN:
refresh: timeout retrying without EDNS master 192.168.0.53#53 (source
0.0.0.0#0)
Oct 21 15:53:43 nstest1 named[15684]: general: debug 1: queue_soa_query:
zone superfly.org/IN: enter
Oct 21 15:53:43 nstest1 named[15684]: general: debug 1: soa_query: zone
superfly.org/IN: enter
Oct 21 15:54:28 nstest1 named[15684]: general: debug 1: refresh_callback:
zone superfly.org/IN: enter
Oct 21 15:54:28 nstest1 named[15684]: general: info: zone superfly.org/IN:
refresh: retry limit for master 192.168.0.53#53 exceeded (source 0.0.0.0#0)
Oct 21 15:54:28 nstest1 named[15684]: general: debug 1: queue_xfrin: zone
superfly.org/IN: enter
Oct 21 15:54:28 nstest1 named[15684]: general: info: zone superfly.org/IN:
Transfer started.
Oct 21 15:54:28 nstest1 named[15684]: general: debug 1: zone superfly.org/IN:
requesting IXFR from 192.168.0.53#53
Oct 21 15:54:28 nstest1 named[15684]: xfer-in: info: transfer of '
superfly.org/IN' from 192.168.0.53#53: connected using 192.168.0.1#32903
Oct 21 15:54:28 nstest1 named[15684]: general: debug 1: zone superfly.org/IN:
zone transfer finished: up to date
Oct 21 15:54:28 nstest1 named[15684]: xfer-in: info: transfer of '
superfly.org/IN' from 192.168.0.53#53: end of transfer

The log is from slave name server and as you can see the zone transfer
finished successfully. What I do not understand is what "timeout retrying
without EDNS master" means and later "retry limit for master
192.168.0.53#53exceeded". This is a test environment, no high load or
firewalls that can
prevent the normal behaviour. Everything seems ok in the master's log. I
experience the same problem on two separate test environments. BIND 9.4.2-P2
running on Debian.

named.conf

 options
{
        directory "/var/named";
        listen-on { any; };
        listen-on-v6 { any; };
        pid-file "/var/run/named.pid";
        notify no;
        recursion no;
        zone-statistics yes;
        querylog yes;
//      match-mapped-addresses yes;

//////// access control ////////
        allow-notify { none; };
        allow-query-cache { none; };
        allow-query { any; };
        allow-recursion { none; };
        allow-transfer { none; };
        tcp-clients 500;
        hostname none;
        version none;

        acache-enable           yes;
        max-acache-size         64M;
        additional-from-auth    no;
        additional-from-cache   no;
        check-sibling           no;
        minimal-responses       yes;
        statistics-file         "/data/named_stats.txt";
        memstatistics-file      "/data/named_mem_stats.txt";
};

// slave testzone
zone "superfly.org" {
        type slave;
        file "/var/named/superfly.slave";
        allow-notify { 192.168.0.53; };
        masters { 192.168.0.53; };
        allow-query { any; };
};

ena