[SOLVED] I have successfully solved this issue. This what I do

Clidk droplet -> your droplet name -> Setting -> Rename
Rename your host to "domain.tld"
important thing is ----> we MUST WAIT for DNS update.

Reverse DNS is automatically configured for your IPs based on the hostname that you provide for your virtual server.

I just renamed my droplet to FQDN, e.g. host.domain.com and now it works, i guess:
~$ host 198.211.121.70
70.121.211.198.in-addr.arpa domain name pointer host.domain.com.

hostname that we provide in as in running hostname in linux or the name of the droplet?

Thanks!

The name of the droplet during creation.

This doesn't seem to work.

willem@navelpluis:~$ host 192.81.223.155
Host 155.223.81.192.in-addr.arpa. not found: 3(NXDOMAIN)

Ditto, not working for myself either.
host 198.211.112.91
Host 91.112.211.198.in-addr.arpa. not found: 3(NXDOMAIN)

Are you going to fix this? That's the only thing that prevent me to use your hosting.
Thanks.

was this suppose to be fixed? Mine comes back not found.

Please open up a ticket if you're still experiencing this problem. Thank you!

I have rename my droplet to FQDN, e.g. mydomain.com , it still not working.
I am sure that this is not a bug, but maybe we need more detail explanation how to do it.

robby_candra,

yet this solution is not working. How long it takes to update the dns? Thx.

@gigliozzi: What's the IP address?

I need clarify how this works - if I name my droplet example.tld (even if I don't have example.com or example.org, etc pointing to it) this will enable reverse DNS after it propagates?

@Jason: Yes, however it would be an "invalid" PTR/rDNS record since it doesn't point back to the droplet.

How do I check if the reverse DNS is set up?

@migmarshall: You can use http://mxtoolbox.com/ReverseLookup.aspx to query your IP for a PTR record.