When recipients open your email, showing your company name in the "From" or "Sender" field is far more professional — and more trustworthy — than displaying "Sent by Mailgun" or another third-party service. Configuring reverse DNS (rDNS) on your dedicated IP is how you make that happen.
Proper rDNS setup improves deliverability, reduces the chance emails are flagged as spam, and keeps your branding consistent across every campaign you send.
What is Reverse DNS (rDNS)?
Reverse DNS is essentially the opposite of a standard DNS lookup. Rather than mapping a domain name to an IP address, rDNS translates an IP address into its associated hostname. This works for both IPv4 and IPv6 addresses and is used to verify the authenticity of the server sending your email.
In practice, rDNS converts the IP address of your sending mail server into a hostname (e.g., mail.yourcompany.com). Mailbox providers perform this lookup to confirm that the IP belongs to a legitimate domain. In email sending, this allows your company name — not "Sent by Mailgun.com" — to appear as the sender in recipients' inboxes.
rDNS configuration for your dedicated IP is not the same as masking the CNAME of mailgun.org in your DNS settings. These are two separate configurations. rDNS specifically controls what hostname appears when a mailbox provider looks up your sending IP address.
Correct rDNS setup ensures your company name is shown as the sender, improves inbox placement, and builds recipient trust — all without the recipient ever seeing the underlying delivery infrastructure.
Common rDNS Mistakes
Accurate rDNS configuration is critical for deliverability and sender reputation. These are the three most common mistakes to avoid:
A PTR (Pointer) record is required to verify that your sending mail server matches the IP address in the email. Without a valid PTR record, mailbox providers cannot confirm your identity. Ensure your PTR record is correctly configured and returns a valid hostname for the IP being queried.
The hostname returned by your PTR record must resolve back to the same IP address — and vice versa. This bidirectional check is called Forward-Confirmed Reverse DNS (FCrDNS). A mismatch causes lookup failures and reduces trust.
Example: If your PTR record returns mail.yourwebsite.com for IP 8.8.8.8, then a forward DNS lookup of mail.yourwebsite.com must also resolve to 8.8.8.8.
If the hostname in your PTR record doesn't resolve to any IP at all, mailbox providers will flag this as a significant trust issue — which can lead to delivery failures. Always verify that your A record is correctly published before submitting the hostname for rDNS.
Your PTR record must point to a valid hostname, and that hostname's A record must resolve back to the same IP. Both directions must be consistent and resolvable.
How to Set Up rDNS
rDNS can only be configured on a dedicated IP. Shared IPs do not support this because rDNS resolves to only one hostname per IP address. A dedicated IP is required for this setup.
Follow these steps to configure rDNS for your dedicated IP:
Log in to your DNS hosting provider and add an A record pointing your chosen hostname to your dedicated IP address. The record format will look like:
Go to Agency Settings → Email Service.
In the SMTP Service tab, click Dedicated Domain And IP in the LeadConnector section.
In the Dedicated IP section, click the three-dot menu next to your dedicated IP and select Reverse DNS (PTR).
Enter the same hostname you used in your A record (e.g., mail.yourcompany.com). The PTR record will be updated on the back end to point to the hostname you provide.
Once the PTR record is updated, your dedicated IP will resolve to the hostname you configured. Mailbox providers will now display your company name as the sender rather than a third-party service name.
Frequently Asked Questions
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