Ptr not updating records in dns
Many companies, including your own ISP might offer DNS hosting on your behalf, but make sure they offer a web based interface which allows you to have some control over your DNS records and make sure they offer good technical support.
All of their interfaces are different, but they accomplish the same basic thing; they allow you to publish your hostnames and important DNS records such as the ones mentioned in this article to the Internet.
Virtually all DNS Hosting Provider provide a web browser based control interface used to modify your DNS records, and should provide the technical support needed if you get stuck trying to modify any of the DNS records discussed in this article.
Caller-ID was an earlier way to do what SPF does today.
As with SPF, Caller-ID gives other mailservers a way to verify that mail claiming to be from your domain is from one of your IP addresses.
For example, you might log into the web portal for the domain and create an "A" record for "mail" for 192.0.2.21.
This would create a mail.published on the Internet.