Troubleshooting: Missing PTR (Reverse DNS) Record

If you see DNS query name does not exist or similar PTR-related errors on tool.tl, it means your outbound mail server's IP address is missing a Reverse DNS (PTR Record).

What is a PTR Record?

A PTR record is the inverse of an A record. While an A record points a domain to an IP, a PTR record points an IP back to a domain. * Purpose: It is a cornerstone of email spam filtering. Recipient servers (like Gmail) verify if the IP connecting to them has a PTR record that matches the sender's domain. * Impact: Without a PTR record, your emails are highly likely to be marked as spam or rejected entirely.

Solution: Set Up Reverse DNS

PTR records are usually NOT set in your domain's DNS panel (like Cloudflare or GoDaddy). They must be configured in your VPS/Server Provider's control panel.

How to set it up:

1. Vultr: Go to Instance -> Settings -> IPv4 -> Click Reverse DNS next to the IP address.
2. DigitalOcean: Go to Droplets -> Networking -> Edit the PTR record for the IP.
3. AWS/GCP: Often managed through the networking console or Elastic IP settings.

Rule of thumb:

The PTR record value should match your mail server's FQDN (Hostname), such as mail.yourdomain.com.

How to Verify?

Once configured, you can verify it manually:

nslookup 1.2.3.4 (Replace with your server IP)
# OR
dig -x 1.2.3.4

If it returns your domain name, the configuration is correct. Go to the Email Diagnostics Tool for testing.

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