dns for mail server

Dear Experts:

Iam in process of configuring the split dns for the zimbra mail server which is behind the firewall, as of now we have outsourced the mail services for which the relay server (fetch mails) is placed in the office (LAN) now we have decided to configure the mail server in the LAN for the same domain.

For this i have taken the step of adding the IP address (public ip ) in the domain control panel for the MX record and set the value higher than the existing.
Now i will not able to install the server as mail.abc.com as it is already there and do not want to disturb hence installed mail server as srv1.abc.com and about to configure the split dns here i have doubts mentioned below:
1. while configuring the split dns in the hosts file of the new mail server what should i give
127.0.0.1            localhost.localdomain   localhost
192.168.1.250      srv1.abc.com       mail        
                 OR
192.168.1.250       srv1.abc.com       srv1

2. created  file /etc/bind/db.abc.com

;
; BIND data file for abc.com
;
$TTL    604800
@       IN      SOA     mail OR srv1.abc.com. admin.abc.com. (
                         070725         ; Serial
                         604800         ; Refresh
                          86400         ; Retry
                        2419200         ; Expire
                         604800 )       ; Negative Cache TTL
;
@       IN      NS      mail OR srv1
        IN      MX      10 mail OR srv1
        IN      A       192.168.1.250
mail or srv1    IN      A      192.168.1.250

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please suggest me in the above whether it should be mail OR srv1