Reverse DNS White Labeling for Dedicated IP
Overview
When you send emails using a dedicated IP, you can configure Reverse DNS (rDNS) to show your company's domain name as the sender instead of a third-party service. This enhances your brand's professionalism, builds trust with recipients, and improves email deliverability by reducing the likelihood of your messages being marked as spam.
What is Reverse DNS (rDNS)?
Reverse DNS is a process that translates an IP address back to a hostname. While standard DNS looks up the IP address for a domain name, rDNS performs the opposite action. Mail servers use rDNS to verify that the IP address sending an email is legitimately associated with the domain it claims to represent. For email sending, this means the recipient's email client can display your chosen hostname (like mail.yourcompany.com) rather than a generic service name.
It is important to note that configuring rDNS for your dedicated IP is different from other domain masking settings. rDNS specifically controls the hostname that appears when a receiving mail server performs a lookup on your sending IP address.
Common rDNS Mistakes
Proper rDNS configuration is essential for maintaining a good sender reputation. Here are common errors to avoid:
Incorrect or Missing PTR Record
A PTR (Pointer) record is necessary to map your IP address to a hostname. If this record is missing or incorrect, mailbox providers cannot verify your server's identity, which can harm deliverability.
Mismatched Hostname
The hostname returned by the PTR record must correctly resolve back to the original IP address. This two-way verification is known as Forward-Confirmed Reverse DNS. A mismatch between the PTR record and the corresponding A record will cause lookup failures and reduce trust.
Unresolvable Hostname
If the hostname specified in your PTR record does not resolve to any IP address, it will be seen as a significant trust issue by email providers and likely lead to delivery problems. Always ensure your A record is properly set up before submitting the hostname for rDNS.
The key takeaway is that your PTR record must point to a valid hostname, and that hostname's A record must point back to the same IP address.
How to Set Up rDNS
rDNS configuration requires a dedicated IP address, as shared IPs cannot be uniquely assigned to a single hostname. Follow these steps to set it up.
Step 1: Add an A Record
Log in to your DNS hosting provider and create an A record that points your chosen hostname (for example, mail.yourdomain.com) to your dedicated IP address.
Step 2: Navigate to Agency Settings
In your CRM, go to Agency Settings and select Email Service.
Step 3: Open Dedicated Domain and IP
Within the SMTP Service tab, locate the CRM section and click on Dedicated Domain And IP.
Step 4: Open Reverse DNS (PTR) Settings
In the Dedicated IP section, find the three-dot menu next to your IP address and select Reverse DNS (PTR).
Step 5: Enter Your A Record Hostname
Enter the exact hostname you used when creating your A record. The system will then update the PTR record on the backend to point your IP to this hostname.
Once the PTR record is updated, your dedicated IP will resolve to your chosen hostname, and mailbox providers will display your company name as the sender.
Frequently Asked Questions
Can I set up rDNS on a shared IP?
No. rDNS can only be configured on a dedicated IP because it resolves one IP address to a single hostname. Shared IPs are used by multiple senders and cannot be assigned a unique hostname.
What is a PTR record and why is it important?
A PTR record maps an IP address back to a hostname. Email providers use it to authenticate the sending server. A missing or incorrect PTR record is a common reason for emails to be rejected or filtered as spam.
Does rDNS replace DKIM or SPF?
No. rDNS, DKIM, and SPF are separate authentication methods that work together. DKIM signs your email content, SPF authorizes your sending IPs, and rDNS verifies your server's identity. For optimal deliverability, you should correctly configure all three.
How long does it take for rDNS changes to take effect?
Backend PTR record updates are usually applied quickly, but full DNS propagation can take from a few minutes up to 48 hours, depending on TTL settings and DNS resolver caches.
How can I verify my rDNS setup?
You can use online DNS lookup tools to perform a reverse DNS lookup on your IP address. The tool should return the hostname you configured. You should also perform a forward lookup on that hostname to confirm it resolves back to your IP address.