Promoting a slave to master gives syntax error

[Theodotos Andreou]

Hello to all,

I have a task to clone a black box IPAM to a bind DNS server. Actually 
the black box is using bind in the backend but the manufacturer does not 
provide any shell access. Only a crappy GUI. So I do not have access to 
the text zone files. Just the GUI.

In order to clone all the zones from the original DNS to the clone, I 
setup a bind in slave config and allowed zone transfers for it. This is 
a sample config:

/etc/bind/named.conf.local:

... Output omitted ...

zone "16.2.10.in-addr.arpa" {
         type slave;
         file "db.16.2.10.in-addr.arpa";
         masters { 10.1.12.61; };
};

zone "24.3.10.in-addr.arpa" {
         type slave;
         file "db.24.3.10.in-addr.arpa";
          masters { 10.1.12.61; };
};

... Output omitted ...

After bind restart, the zone transfers an all zones are completed 
successfully. The resultant files are some sort of binary:

# file /var/cache/bind/db.24.3.10.in-addr.arpa
/var/cache/bind/db.24.3.10.in-addr.arpa: data

Now to promote the server to master I changed the configuration to:

/etc/bind/named.conf.local:

... Output omitted ...

zone "16.2.10.in-addr.arpa" {
         type master;
         file "db.16.2.10.in-addr.arpa";
};

zone "24.3.10.in-addr.arpa" {
         type master;
         file "db.24.3.10.in-addr.arpa";
};

... Output omitted ...

But when I restart bind I get a lot of errors like this:

  named[19773]: dns_master_load: db.24.3.10.in-addr.arpa:1: syntax error
  named[19773]: zone 24.3.10.in-addr.arpa/IN: loading from master file db.24.3.10.in-addr.arpa failed: syntax error
  named[19773]: zone 24.3.10.in-addr.arpa/IN: not loaded due to errors.

Apparently the systems expects to see a zone file in text format but 
because it's in binary it fails. I also tested it with:

# named-checkzone 24.3.10.in-addr.arpa /var/cache/bind/db.24.3.10.in-addr.arp
... Output omitted ...
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:16: syntax error
dns_master_load: /var/cache/bind/db.24.3.10.in-addr.arpa:17: syntax error
/var/cache/bind/db.24.3.10.in-addr.arpa: file does not end with newline
zone 24.3.10.in-addr.arpa/IN: loading from master file /var/cache/bind/db.24.3.10.in-addr.arpa failed: syntax error
zone 24.3.10.in-addr.arpa/IN: not loaded due to errors.

I know I must be doing something fundamentally wrong here but I couldn't 
find a guide how to do this properly. Any ideas?

I am using bind version 9.9.5-3-Ubuntu ( the stock binary that comes 
with Ubuntu 14.04 64 bit) and the compiled parameters are:
named[7817]: built with '--prefix=/usr' '--mandir=/usr/share/man' 
'--infodir=/usr/share/info' '--sysconfdir=/etc/bind' 
'--localstatedir=/var' '--enable-threads' '--enable-largefile' 
'--with-libtool' '--enable-shared' '--enable-static' 
'--with-openssl=/usr' '--with-gssapi=/usr' '--with-gnu-ld' 
'--with-geoip=/usr' '--with-atf=no' '--enable-ipv6' '--enable-rrl' 
'--enable-filter-aaaa' 'CFLAGS=-fno-strict-aliasing -DDIG_SIGCHASE -O2'