/usr/sbin/host -t mx example.net

/etc/bind/petka.pl

$TTL 86400
$ORIGIN petka.pl.
@   IN   SOA   ns1.petka.pl root.petka.pl. (
         20080913
         1200
         1200
         2419200
         86400 )

@              IN    NS    ns1.petka.pl.
@              IN    NS    ns2.petka.pl
@              IN    MX    mail.petka.pl.
@              IN    A     91.121.141.32

// This is the primary configuration file for the BIND DNS server named.
//
// Please read /usr/share/doc/bind/README.Debian for information on the
// structure of BIND configuration files in Debian for BIND versions 8.2.1
// and later, *BEFORE* you customize this configuration file.
//

include "/etc/bind/named.conf.options";

// reduce log verbosity on issues outside our control
logging {
   category lame-servers { null; };
   category cname { null; };
};

// prime the server with knowledge of the root servers
zone "." {
        type hint;
        file "/etc/bind/db.root";
};

// be authoritative for the localhost forward and reverse zones, and for
// broadcast zones as per RFC 1912

zone "localhost" {
        type master;
        file "/etc/bind/db.local";
};

zone "127.in-addr.arpa" {
        type master;
        file "/etc/bind/db.127";
};

zone "0.in-addr.arpa" {
        type master;
        file "/etc/bind/db.0";
};

zone "255.in-addr.arpa" {
        type master;
        file "/etc/bind/db.255";
};

zone "petka.pl"{
      type master;
      file "/etc/bind/petka.pl";
      allow-update { none; };
      allow-transfer {213.186.33.80};
      notify yes;
};

// add local zone definitions here
include "/etc/bind/named.conf.local";