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Reverse DNS (PTR record) maps your server's IP address back to a hostname — the opposite of a normal A record. Nearly every major mailbox provider checks this before accepting mail, making it one of the most important email deliverability requirements.

What Is a PTR Record?

IP Address: 203.0.113.10
PTR Record: mail.yourdomain.com

A reverse lookup of the IP should return the hostname, and a forward lookup of that hostname should return the same IP — this match is called Forward-Confirmed Reverse DNS (FCrDNS).

Step 1 — Choose a Hostname

Use a subdomain dedicated to mail, such as mail.yourdomain.com.

Step 2 — Create the Forward A Record

Type: A
Name: mail
Value: YOUR_SERVER_IP

Step 3 — Set the Server's Hostname

sudo hostnamectl set-hostname mail.yourdomain.com

Verify:

hostnamectl

Step 4 — Request the PTR Record from Your VPS Provider

Unlike A records, PTR records are controlled by whoever owns the IP address block — typically your hosting provider, not your domain registrar. Set it through your provider's control panel, or submit a support ticket requesting:

YOUR_SERVER_IP → mail.yourdomain.com

Step 5 — Configure HELO/EHLO to Match

Your mail server's HELO/EHLO greeting should use the same hostname. For Postfix:

sudo nano /etc/postfix/main.cf

myhostname = mail.yourdomain.com

sudo systemctl restart postfix

Step 6 — Verify the Configuration

Check the PTR record:

dig -x YOUR_SERVER_IP +short

Check the forward A record:

dig A mail.yourdomain.com +short

Both should reference each other consistently — confirming FCrDNS is correctly configured.

Common Mistakes

• PTR record pointing to a generic hostname assigned by the hosting provider instead of your own domain
• Forward A record missing or pointing to a different IP than the PTR record
• HELO/EHLO hostname not matching the PTR hostname
• Using a shared/dynamic IP where you can't control the PTR record at all

Common Errors

PTR request denied or unavailable — some budget hosting plans don't support custom PTR records; confirm this capability before choosing a VPS for email marketing.

Emails still flagged despite correct PTR — rDNS is one of many factors; also verify SPF, DKIM, DMARC, and IP warm-up status.

Best Practices

• Use a dedicated IPv4 address specifically to maintain full control over its PTR record
• Keep the hostname consistent across DNS, server hostname, and mail server HELO configuration
• Verify FCrDNS with dig after any server or IP change

FAQ

Who can set a PTR record — me or my domain registrar?
Only the owner of the IP address block (your VPS/hosting provider) can create or modify PTR records — not your domain registrar, since it's tied to IP ownership, not domain ownership.

Related Articles

• How to Configure SPF, DKIM, and DMARC (Complete Guide)
• How to Set Up a VPS for Email Marketing (Complete Guide)
• How to Install and Configure Postfix as a Mail Transfer Agent