How to set PTR-records for mail server? (Bind9 & Webmin)

Question

I have dedicated Ubuntu LAMP-server with Bind9, Webmin and Mail server.

My IP:
12.345.678.900
My host: (domain is pointed to this as 1. nameserver)
ns999999.ip-12-345-678.eu
My domain:
www.examp.le
My second nameserver:
ns.nameserver.com

I have successfully set master (Forward zone) record to Bind like that:

examp.le.   IN  SOA ns999999.ip-12-345-678.eu. webmaster.examp.le. (
        1394802155
        10800
        3600
        604800
        38400 )
examp.le.   IN  NS  ns999999.ip-12-345-678.eu.
examp.le.   IN  MX  10 mail.examp.le.
examp.le.   IN  NS  ns.nameserver.com.
examp.le.   IN  A   12.345.678.900
*.examp.le. IN  A   12.345.678.900

That zone is working and when I put examp.le to my browser it works. I have mail server running in the same server in host mail.examp.le. I have had some problems with sending and receiving mail and I think that one reason is the PTR-record. I mean I don't have any PTR-records. Also some public DNS-tests say: "THERE ARE NO PTR RECORDS FOR YOUR MAIL SERVER 'mail.examp.le' IN 'ns999999.ip-12-345-678.eu'"

My problem is that I don't know how to set those PTR records for mail.examp.le. I have tried to google many hours and so on but I can't set it.

Thank you very much for your help.

Answer 1

First of all: A PTR record is most often set by your ISP. Probably nothing you can set yourself. It a record under your IP number not your domain name. Contact your ISP and ask them to set up the PTR record.

You should also look up SPF records and DKIM. If you are experiencing that sent mails end up in the trash can!

Some good reading on the subject: http://www.allaboutspam.com

Some other reading on PTR records: http://www.itworld.com/networking/362601/how-setup-reverse-dns-and-ptr-records

EDIT

The PTR record should point to the domain name sending the mail. for example: if you are sending mail from admin@example.com the PTR record should point to example.com

Answer 2

For DigitalOcean you would need to set the droplet name the same as the domain name and the PTR will be configured automatically

Reverse DNS (PTR) records are automatically created based on the name that you give your droplet in the Control Panel. If you want to rename a droplet, go to its page in the Control Panel, click directly on the existing Droplet name, and enter a new name there.

There are two things to keep in mind. That new name has to be a fully-qualified domain name - that means that "example.com" will generate a valid PTR record, but a name like "my-ubuntu-droplet" will not generate a PTR record. Also, if you're using IPv6 on your droplet, a PTR record will only be generated for the first IPv6 address assigned to the droplet, not all 16 IPv6 addresses which are available to the droplet.