I have been waiting the DNS propagation for almost 24 hours. I'am no impatient, but I want to know if I configured my zone good or I have any error in it.

I think that is good, because if I use my server dns like my DNS secondary I can resolve and lookup host well.

;
; BIND data file for mydomain.net
;
$TTL    86400
@   IN  SOA mydomain.net. mydomain.net. (
        20120629    ; Serial
           10800    ; Refresh 3 hours
            3600    ; Retry 1 hour
          604800    ; Expire 1 week
         86400 )    ; Negative Cache TTL
;
@       IN  NS  ns1
@       IN  NS  ns2

    IN  MX  10 mail

ns1     IN  A   5.39.X.Y
ns2     IN  A   5.39.X.Z

There is not any errors in /var/syslog about bind daemon. Is everything correct? Do I only need to wait up to 48 hours for the right DNS propagation?

My nslookup from a remote machine with the nameserver of the bind host:

$ nslookup mydomain.net
Server:     bind-host-ip
Address:    bind-host-ip#53

Name:   mydomain.net
Address: domain-ip