Reverse DNS setup not working - BIND on CentOS 7

Question

I haven't setup BIND before but am quite knowledgable with DNS (I'm from the Windows world). I'm having a reverse DNS issue. Forward DNS is working fine for the zone int.linuxlab

Here are the relevant lines from named.conf

zone "253.168.192.in-addr.arpa" IN {
    type master;
    file "253.168.192.in-addr.arpa";
    allow-update { 192.168.253.0/24 ;};
};

and here is the configuration file 253.168.192.in-addr.arpa

     $TTL 3600 
@   IN SOA  daniinf.int.linuxlab hostmaster.daniinf.int.linuxlab. (
                20160402; serial
                3600    ; refresh
                    1800    ; retry
                1W  ; expire
                3H )    ; minimum
IN  NS  daniinf.int.linuxlab.
;   IN  A   daniinf 192.168.253.5 
$ORIGIN 253.168.192.in-addr.arpa.
5   IN  PTR     daniinf.int.linuxlab.
6   IN  PTR     daniswalker.int.linuxlab.

not sure what I'm doing wrong on this, can someone help?

Thanks a lot