Setting Up an rDNS Record

Setting up a reverse DNS (rDNS) record, also known as a PTR (Pointer) record, is crucial for ensuring your emails are authenticated and not marked as spam. This guide will walk you through the process of creating a PTR record for your domain, helping you establish a reliable and trustworthy email presence.

What is a PTR Record?

A PTR record performs the reverse function of an A record. While an A record maps a domain name to an IP address, a PTR record maps an IP address back to a domain name. This reverse DNS lookup is essential for email authentication.

Why Set Up an rDNS Record?

• Email Authentication: Most email providers perform a DNS lookup along with a reverse DNS lookup and compare the results. If they don’t match or if a PTR record doesn’t exist, emails may be marked as spam or rejected.
• Spam Prevention: Email servers and anti-spam filters use reverse DNS lookup to verify that the sending domain matches the one mentioned in the email’s "From" field. Properly configured rDNS helps prevent your emails from being treated as spam.

Steps to Set Up an rDNS Record

Let's dive into the steps for setting up an rDNS record. Note that the exact steps may vary depending on your DNS provider.

Step 1: Access Your DNS Settings

Log in to your domain registrar or DNS hosting provider’s website. Look for a section related to DNS or domain settings.

Step 2: Create a Reverse DNS Zone

In your DNS settings, find an option for creating a reverse DNS zone. If you can’t access this option, contact your domain provider’s support and request assistance in setting up a PTR record for your IP address.

Step 3: Find Out Your Hosting IP Address

Identify your domain’s IP address. For example, if your IP address is 192.168.0.111, you need to reformat it for the PTR record. Omit the last three digits and reverse the order of the remaining numbers, resulting in 0.168.192.

Next, add the .in-addr.arpa suffix to this reversed IP. So, your hostname will be 0.168.192.in-addr.arpa.

Note: The .in-addr.arpa suffix is used for IPv4 addresses. For IPv6 addresses, use the ip6.arpa suffix.

If you’re unsure which IP address to use, contact your domain provider for assistance.

Step 4: Create a PTR Record

Now, create the PTR record within your reverse DNS zone:

1. In your DNS settings, click "Add a new record" and select the PTR type.
2. In the "Hostname" or "Reverse zone" field, enter the formatted value of your PTR record (e.g., 0.168.192.in-addr.arpa).
3. In the "Points to" field, enter the domain you’d like the PTR to point to (e.g., emailserver.example.com).
4. Set the TTL (Time to Live) value as needed, or leave it as "Auto".

Example PTR Record

HostTypePoints toTTL0.168.192.in-addr.arpaPTRemailserver.example.comAuto

Important Considerations

• Avoid Multiple PTR Records: Having multiple PTR records for a single IP can cause DNS/rDNS lookup failures and reduce email deliverability.
• Update Existing Records: If your domain has an existing PTR record that fails the DNS check, update the current record instead of creating a new one.

By following these steps, you can set up a reliable rDNS record for your domain, ensuring that your emails are properly authenticated and not marked as spam. If you encounter any issues, don’t hesitate to reach out to your domain provider for assistance.