Hi I had deployed a Zimbar 8.0.2 opensource for my office, due a mistake I made while installation we had landed in reverse dns issue.
And mails sent from our server are blocked by some domains and getting rejected. Checked with a online MX lookup tool I am getting error as in image below
dns error.JPG

and my DNS records are listed below

Forward
$TTL 14400
@ IN SOA ns1.example.com. root.ns1.example.com. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
@ IN NS ns1.example.com.
IN MX 10 example.com.
IN A 10.0.2.11
ns1 IN A 10.0.2.11
mail IN A 10.0.2.11
www IN A 10.0.2.11

Reverse
$TTL 14400
@ IN SOA ns1.example.com. root.ns1.example.com. (
0 ; serial
1D ; refresh
1H ; retry
1W ; expire
3H ) ; minimum
@ IN NS ns1.example.com.
11.2.0.10.in-addr.arpa. IN PTR ns1.example.com.
11.2.0.10.in-addr.arpa. IN PTR mail.example.com.

I wish to change all ns1.example.com to mail.example.com, if I change the DNS record I know sure my email service will get affected. Can anybody help me how can I over come it. I wish to retain the users and domains configured to it.

Thank you
Regards
Vivek