PTR record term can be understood by actually it is IP pointing to the domain. It is also known as reverse DNS record. It is so-called reverse DNS record because it acts as an opposite to Domain Name System. A Domain Name System is used to point domains to IP addresses but in case of PTR record or known as reverse DNS record it acts opposite. One PTR record can be configured for single IP and pointing that IP to a single domain. PTR or Reverse DNS is responsible to send email from your computer or laptop to the internet. It also adds credibility to the e-mail server itself.
These records are mostly used by spam filters to find the suspiciousness of an email. The reason behind is that spammer does not have valid PTR records since they use fake domains and dial-up IP addresses to send spam emails.
How does it look?
Domain Name System
IP is 126.96.36.199 points to your domain www. xyz.com
PTR Record or Reverse DNS
If no PTR record found, you may get these errors following:
IP Address 188.8.131.52.5 does not have a PTR record in DNS
So how does it impact my email going to spam?
Many servers will check your PTR record or reverse DNS record to verify the anti-spam check procedure. It is recommended that your “A” records should match your PTR record. If your record does not match with each other, then it is sure that ISPs will mark you as Spam or your email may be blocked for sending outgoing emails without valid PTR record for your sending host. If you’re Computer or Laptop has been infected by Trojan, Bot or any Emailer Program then you are likely to get listed on RATS-DYNA blacklist list. In a different case, you are email user and you have a dynamic IP Address and may need to contact your ISP for help. If you run a domain name and are using your ISP for SMTP-Authentication, try contacting your DNS Provider to use their SMTP-Services instead.
You also have to take care that PTR Record created for both the Exchange server WAN IP Address at the Domain Name Registrars DNS system and have their ISP create a PTR Record for the Domain pointing to the Exchange Server WAN IP Address.
Your (ISPs) Internet Service Providers will help you to set up valid PTR record for your IPS. You have to call them and follow-up and ask them about the PTR record validation they will check through their system. Normally you should have one PTR record for one IP, but you can add multiple PTR records in your DNS. But remember multiple PTR on single IP will have a negative impact on your reputation.
Remember, AOL and Comcast ISPs will reject your emails if they do not find valid PTR record.