Reverse DNS (rDNS)

01

What is Reverse DNS?

Reverse DNS (rDNS or PTR record) does the opposite of normal DNS: instead of translating a name to an IP, it translates an IP to a hostname.

It's especially important for servers that send email: many mail servers reject emails if the sender doesn't have a correctly configured PTR record.

02

How to Check the Current PTR Record

bash
# From the server
host SERVER_IP

# With dig
dig -x SERVER_IP

# With nslookup
nslookup SERVER_IP
03

How to Configure Reverse DNS

The PTR record is managed by the IP provider (that's us), not by your domain registrar.

To configure it:

The name you enter in the PTR must correspond to an A record pointing to your server's IP. In other words, mail.example.com must resolve to your server's IP.

  • Access your client panel
  • Select your server or your IP
  • Look for the Reverse DNS or PTR Record section
  • Enter the desired hostname (e.g., mail.example.com)
  • Save
04

Recommended Configuration for Email Sending

If your server sends email, configure the PTR so it matches your mail server's hostname. Example:

  • Server IP: 1.2.3.4
  • PTR record: mail.example.com
  • A Record: mail.example.com → 1.2.3.4
05

Email Configuration Verification

You can test whether your IP is blacklisted or your PTR is correct with these tools:

  • MXToolbox: blacklist and PTR check
  • mail-tester.com: comprehensive email configuration test

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