Reverse DNS (rDNS) Setup on Major VPS Providers

Reverse DNS: Provider-by-Provider Setup

Every email server needs a PTR record. Without it, most mailbox providers will reject or spam your email. For background on how PTR fits into email infrastructure, see our PTR records guide and VPS comparison. This guide covers PTR setup on every major VPS provider.

What You Need

Before configuring rDNS:

1. Your mail hostname — typically mail.yourdomain.com
2. A forward A record — mail.yourdomain.com → YOUR.SERVER.IP
3. Your server IP — the VPS's primary IPv4 address

The PTR record creates the reverse mapping: YOUR.SERVER.IP → mail.yourdomain.com

Hetzner Cloud

1. Log into console.hetzner.cloud
2. Select your project → select the server
3. Click Networking in the left sidebar
4. Under Primary IPv4, click the IP address
5. In the Reverse DNS field, enter mail.yourdomain.com
6. Click Save

For IPv6 (if needed):

• Same location, under Primary IPv6
• Enter the PTR for the specific IPv6 address your server uses

Propagation: Usually immediate. Verify within 5 minutes.

DigitalOcean

DigitalOcean derives PTR records from your droplet's name:

Method 1: Rename Droplet

1. Log into cloud.digitalocean.com
2. Select your droplet
3. Click the droplet name at the top
4. Rename to mail.yourdomain.com
5. PTR updates automatically

Method 2: API

curl -X PATCH "https://api.digitalocean.com/v2/droplets/DROPLET_ID" \
  -H "Authorization: Bearer $DO_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"name": "mail.yourdomain.com"}'

Note: DigitalOcean's PTR system is unusual — it's tied to the droplet name. If you rename the droplet for other reasons, the PTR changes too.

Propagation: 5-30 minutes.

Vultr

1. Log into my.vultr.com
2. Select your instance
3. Click Settings tab
4. Scroll to IPv4 section
5. Click the Reverse DNS button (pencil icon) next to your IP
6. Enter mail.yourdomain.com
7. Click the checkmark to save

For IPv6:

• Same page, under IPv6 section
• Click Reverse DNS for your IPv6 address

Propagation: Usually within 5-10 minutes.

OVH / OVHcloud

1. Log into ovh.com/manager
2. Navigate to Bare Metal Cloud → IP (or Public Cloud → IP for cloud instances)
3. Find your IP address in the list
4. Click the ... menu → Modify reverse
5. Enter mail.yourdomain.com
6. Click Confirm

Note: OVH requires the forward A record to exist before accepting the PTR. Create the A record first.

Propagation: Can take up to 24 hours. Typically 1-4 hours.

Linode (Akamai)

1. Log into cloud.linode.com
2. Select your Linode
3. Click the Network tab
4. Under IPv4 Addresses, click Edit RDNS next to your IP
5. Enter mail.yourdomain.com
6. Click Save

Note: Linode validates the forward DNS record. Your A record must resolve to the Linode's IP before the PTR is accepted.

Propagation: Usually within 15 minutes.

AWS (EC2 / Lightsail)

AWS requires extra steps:

1. Assign an Elastic IP to your instance (PTR can't be set on dynamic IPs)
2. Submit a request via the AWS rDNS request form
3. Fill in your Elastic IP, desired PTR record, and use case
4. Wait for approval — typically 1-3 business days

AWS also blocks port 25 by default. You must separately request SMTP sending capability through the same form.

Propagation: After approval, usually 24-48 hours.

Verification

After setting the PTR, verify from multiple sources:

# Check from Google's DNS
dig -x YOUR.IP @8.8.8.8 +short
# Expected: mail.yourdomain.com.

# Check from Cloudflare's DNS
dig -x YOUR.IP @1.1.1.1 +short
# Expected: mail.yourdomain.com.

# Verify forward-confirmed rDNS
dig mail.yourdomain.com @8.8.8.8 +short
# Expected: YOUR.IP

# Full SMTP check
# Send email to [email protected]
# The reply includes PTR verification

Common Issues

PTR Doesn't Match EHLO

Your Postfix myhostname must match your PTR record:

postconf myhostname
# Must return: mail.yourdomain.com

# Fix if wrong:
sudo postconf -e "myhostname = mail.yourdomain.com"
sudo systemctl restart postfix

Provider Requires Forward DNS First

OVH and Linode validate that the A record exists before accepting a PTR. Create the A record and wait for propagation before setting the PTR.

Multiple IPs, Wrong One Used

If your server has multiple IPs, verify which one Postfix uses for outbound:

postconf smtp_bind_address
# If empty, Postfix uses the default route IP

Set the PTR on the IP Postfix actually sends from.

Practitioner note: I've wasted more time on DigitalOcean's droplet-name-as-PTR system than I care to admit. Clients rename their droplet to something descriptive like "production-email-v2" and wonder why their PTR changed. If you use DigitalOcean for email, treat the droplet name as a PTR configuration field, not a label.

Practitioner note: AWS is the worst provider for self-hosted email. Port 25 blocked by default, PTR requires a support request, and the approval process can take days. If a client insists on AWS, I recommend using SES for sending and running the mailbox server elsewhere. Don't fight AWS's email restrictions — they're there for a reason, and working around them is painful.

If you need help configuring reverse DNS or debugging PTR-related delivery failures, schedule a consultation — I'll verify your complete DNS chain across all providers.

Sources

• Hetzner: Cloud Networking Docs
• DigitalOcean: PTR Records
• Vultr: Reverse DNS
• AWS: Elastic IP rDNS

---

v1.0 · April 2026