Setting reverse DNS (PTR)

Before installing Reqad, your server's IPv4 address should have a reverse DNS (PTR) record pointing to its hostname. Reqad issues a Let's Encrypt certificate on that hostname, and correct reverse DNS is also important for mail deliverability.

What reverse DNS is

Normal ("forward") DNS turns a name into an IP - server.example.com → 203.0.113.10. Reverse DNS does the opposite: it turns an IP back into a name via a PTR record - 203.0.113.10 → server.example.com. For a mail-capable hosting server, the forward and reverse records should match.

Who sets it

A PTR record is controlled by whoever owns the IP address - that's your VPS / hosting provider, not your domain's DNS zone. You normally set it from your provider's control panel (often labelled Reverse DNS, rDNS or PTR) or by opening a support request.

Steps

Pick a hostname for the server, e.g. server.example.com (a subdomain you control).
Create a forward A record for that hostname pointing to your server's IPv4 address.
In your provider's panel, set the reverse DNS / PTR for the IP to the same hostname.
Wait for it to propagate (usually minutes, sometimes longer).

Verify

From any machine, check that the reverse record resolves to your hostname:

dig -x 203.0.113.10 +short
# or
host 203.0.113.10

It should return your hostname (e.g. server.example.com.). Confirm the forward record matches too:

dig +short server.example.com

This should return the same IP you set the PTR for.

Why Reqad needs this. The installer requests a Let's Encrypt certificate for your server's hostname, and mail servers check that a sending IP's reverse DNS matches its forward record. Getting PTR right up front avoids certificate and email-delivery problems later.

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