Assume internal IP is 172.50.110.123, public IP is 201.33.190.172 and domain is abc.com.my host by other. NAT is done at firewall.

/etc/hosts
Code:
127.0.0.1 localhost
172.50.110.123 mail.abc.com.my mail
If domain abc.com.my has an mx record mail.abc.com.my, can i have another host name rather than "mail"?

/etc/resolv.conf
Code:
search abc.com.my
nameserver 127.0.0.1
nameserver 202.188.0.133
nameserver 202.188.1.5
/etc/bind/named.conf.local
Code:
zone "mail.abc.com.my" {
type master;
file "/etc/bind/db.mail.abc.com.my";
};

zone "110.50.172.in-addr.arpa" {
type master;
file "/etc/bind/db.172";
};
Th zone should be abc.com.my or mail.abc.com.my?

/etc/bind/db.mail.abc.com.my
Code:
;
; BIND data file for local loopback interface
;
$TTL    604800
@       IN      SOA     mail.abc.com.my. root.abc.com.my. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;

@       IN      NS      mail.abc.com.my.
@       IN      A       172.50.110.123
mail    IN      A       172.50.110.123
What mean by @ stated above. The @ IN A 172.50.110.123 is needed?

/etc/bind/db.172
Code:
;
; BIND reverse data file for local loopback interface
;
$TTL    604800
@       IN      SOA     mail.abc.com.my. root.abc.com.my. (
                              2         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      mail.
154     IN      PTR     mail.abc.com.my.
Does the mail. represent the FQDN mail.abc.com.my?

I installed the zimbra already and it worked fine but I just wonder there is some wrong configuration. To install zimbra in NAT environment using config files above, anything wrong or can be impoved? May I know why the email is user@mail.abc.com.my and it work? Not that it should be user@abc.com.my? The MX record is abc.com.my IN MX 0 mail.abc.com.my; mail.abc.com.my IN A 201.33.190.172. I don't want to create another domain after installation. I think about change the domain name when come to "DNS ERROR resolving MX for mail.abc.com.my" installation step but with those config file I listed above, this step didn't appear until finish.

Your help can made me have better understanding, thank you.