The IP reverse resolution is like the caller ID feature that reveals caller's identity of an incoming call.
Contact your ISP to reversely resolve your IP address into your domain name. Therefore, the DNS PTR record matches your domain name and does not contain strings randomly given by ISP, such as pppoe, dynamic, dialup and dial-up. Those keywords may cause major recipient mail servers think your server being a spam source and thus reject email messages from your end.
A. Why people often skip this step?
Answer: Once ISP receives your IP reverse resolution request, it takes 2 to 3 days or even longer for this DNS records to be effective throughout Internet. Some people do not bother to wait so may as well skip it.
B. When do I apply for IP reverse resolution?
Answer: Once your registered domain name is ready for use, submit the resolution request to your ISP. While waiting, you can go ahead to manage your DNS hosting records.
C. What do I need to apply for IP reverse resolution?
Answer: You need:
1. Your ADSL account information
2. Your registered domain name
3. Your contact information such as phone number, email address and company business license number
D. How do I apply for IP reverse resolution?
Answer: Go to your ISP website and search for related information or simply call your ISP's technical support.
E. A List of commonly-used ISPs, you may be able to find IP reverse resolution information in it.