> ## Documentation Index
> Fetch the complete documentation index at: https://help.onetsolutions.net/llms.txt
> Use this file to discover all available pages before exploring further.

# Reverse DNS (PTR)

> Configure the PTR / reverse DNS record of your VPS IP address

You can set a custom **reverse DNS** (also called **PTR record**) on your VPS IP address directly from the OnetSolutions control panel. The reverse DNS associates your IP with a domain name and is required by most mail servers to accept your outgoing messages.

<Info>
  **Prerequisites**

  * A VPS with OnetSolutions
  * A domain name that **resolves publicly**, with an **A record** pointing back to your VPS IP (forward-confirmed reverse DNS, or FCrDNS)
  * The value must be a **fully qualified domain name** (FQDN), e.g. `vps.example.com` — IP addresses and wildcards are not accepted
</Info>

## Why set a reverse DNS

<CardGroup cols={2}>
  <Card title="Email deliverability" icon="envelope">
    Most mail servers reject messages from IPs without a valid PTR or with a generic provider PTR.
  </Card>

  <Card title="Trust & reputation" icon="shield-check">
    A consistent forward/reverse pair improves your server's reputation with remote services.
  </Card>
</CardGroup>

## Configure your reverse DNS

<Steps>
  <Step title="Prepare the forward record">
    In your DNS zone, create or verify an **A record** for the FQDN you want to use, pointing to your VPS IP address. Wait for it to propagate before continuing.

    ```
    vps.example.com.   IN   A   203.0.113.42
    ```
  </Step>

  <Step title="Open your VPS in the control panel">
    Log in to [customer.onetsolutions.net](https://customer.onetsolutions.net), go to **My Services**, and select the VPS to manage.
  </Step>

  <Step title="Edit the reverse DNS">
    In the network section of your VPS, locate the **Reverse DNS** field for your IPv4 address and enter the FQDN (for example `vps.example.com`). Save your change.
  </Step>

  <Step title="Wait for propagation">
    The new PTR is applied on our side immediately, but recursive resolvers may cache the previous value. Allow up to 24-48 hours for global propagation.
  </Step>
</Steps>

## Verification

Once the change is propagated, you can verify the reverse DNS from any machine:

```bash theme={null}
# Reverse lookup (IP → FQDN)
dig -x 203.0.113.42 +short

# Forward lookup (FQDN → IP) — must match
dig vps.example.com A +short
```

Both values should match for forward-confirmed reverse DNS to be valid.

## Troubleshooting

<AccordionGroup>
  <Accordion title="The change is rejected or fails to save">
    Check that the FQDN resolves publicly with an A record pointing to your VPS IP. Without that forward record, the reverse DNS cannot be validated.
  </Accordion>

  <Accordion title="Mail servers still reject my emails">
    A valid PTR is necessary but not sufficient. Make sure your domain also has correct **SPF**, **DKIM** and **DMARC** records, and that the email ports are unblocked (see [Network](/vps/network#email-ports)).
  </Accordion>

  <Accordion title="`dig -x` still returns the old value">
    DNS caches can hold the previous value for several hours. Retry from a different resolver (for example `dig -x <ip> @1.1.1.1`) or wait for the TTL to expire.
  </Accordion>
</AccordionGroup>