Quick answer: A PTR (reverse DNS) record maps your server's IP address back to a hostname — the mirror of an A record. Mail servers check it on every connection, and mail from an IP without a matching PTR is routinely rejected. At Cloud2Y you set the PTR for your public IPv4 on the Client Area service page, or via a support ticket if the option is not shown.
Overview
Forward-confirmed reverse DNS (FCrDNS) is the baseline trust check in email: the IP resolves to a hostname (PTR), and that hostname resolves back to the same IP (A record). Because PTR records live in the address space owner's zone — not your domain's — they are managed through Cloud2Y, unlike every other DNS record you set at your registrar.
Before you start
- Choose the hostname, e.g.
mail.yourdomain.com— it should be the machine's real mail hostname (HELO name). - Create the matching A record first:
mail.yourdomain.com → your server IP.
Step-by-step guide
- Log in to the Client Area and open the service under My Services.
- Find the reverse DNS / PTR option for your public IPv4, if shown on the service page, and enter the hostname.
- If the option is not shown, open a support ticket with the IP address and the desired hostname — see how to request a PTR record.
- Verify after propagation:
dig +short -x 203.0.113.10 # expect: mail.yourdomain.com. - Confirm FCrDNS both ways:
dig +short mail.yourdomain.com # expect: 203.0.113.10
Common issues
- PTR set but mail still flagged: the PTR hostname must resolve back to the same IP and match your SMTP HELO — three values, one name.
- Generic PTR left in place: a default provider-style PTR looks like a dynamic host to filters — always set a real hostname before sending mail.
- Old value cached: reverse zones respect TTLs too; give changes time before re-testing.
When to contact support
Open a ticket for any PTR change you cannot make on the service page, for PTRs on additional IPv4 addresses, or for IPv6 reverse zones.
Frequently asked questions
Why do mail servers require a PTR record?
A matching PTR proves the IP is a deliberately configured mail host rather than a dynamic address; many providers reject SMTP connections from IPs without valid reverse DNS.
Where do I set the PTR for my Cloud2Y IP?
On the service page in the Client Area if the reverse DNS option is shown for your IPv4, or via a support ticket stating the IP and the exact hostname you want it to resolve to.
What hostname should the PTR point to?
The real mail hostname of the server, such as mail.yourdomain.com — the same name your SMTP server announces in HELO, with an A record resolving back to the same IP.
Related articles
- How to request a PTR record
- How to avoid email going to spam
- How to configure SPF
- How to configure DNS for email services
Need a hand? Contact Cloud2Y support →
