want to Request our ISp to do rdns/ ptr modify for my Staic IP ot point to my Domain?

Question

we setup a mail server in our local office using Mdaemon Mail Server . We have a Staic ip 123.xxx.123.xxx ( as an example ) and all necessary ports (80 , 25 , 110 ) are made open .

We have a domain abc.com which is not hosted anywhere planning host at our server only after our mail server issue solved ( at port 80 - apache http server ). We have DNS settings made at one of free DNS service provider ( zonomi.com ).

In Zonomi - ( dns service provider) our domain abc.com has following dns records .

1. IP Addresses (A)

abc.com points to 123.xxx.123.xxx

mail.abc.com points to 123.xxx.123.xxx

---

Mail Servers (MX)

mail.abc.com -> abc.com

Name Servers (NS)

ns1.zonomi.com handles DNS for abc.com

ns2.zonomi.com handles DNS forabc.com

after finishing this settings we tried running our mail server but most mails were blocked at gmail , yahoo etc . then we come to know our rdns( reverse dns / ptr not matching )

current static ip 123.xxx.123.xxx rdns check points to 123.xxx.123.xxx.vsnl.net(our ISP - vsnl ) ....

where as our forward dns look up shows

                  123.xxx.123.xxx   - abc.com ( or mail.abc.com ?)

Now we finaly decided to ask our ISP to do necessary change in to our PTR / rDNS setting to point our domain(abc.com or mail.abc.com ) so my question is

what are details i should need to give to my ISP to do Necessary settings on rDNS at its end

ex like domain name , ns records details etc ?

and one more thing

we set up A record abc.com to 123.xxx.123.xxx & mail.abc.com also to 123.xxx.123.xxx and my mx records mail.bac.com to handle abc.com mails

so I want to know what is exact rDNS value abc.com or mail.abc.com should be point against our static IP 123.xxx.123.xxx

what should i tell to my ISP to put in rdns value abc.com or mail.abc.com ????

Answer 1

• If you have domain already registered, you can write real domain - it's safe (and easier debug for possible errors)
• mail RR is or copy-paste error or definition error (missed dot?), check it
• you can ask to write any of two hostnames in reverse zone, both (for shown settings) will work - you have only pass "Paranoid IP check" for hostname (IN A -> IN PTR requests pair) must generate closed ring

PS: you can ever use default hostname of ISP for MX record of your domain and don't ask ISP do something - MX records of any domain can be anywhere outside domain's name-space