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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.
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

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Why set a reverse DNS

Email deliverability

Most mail servers reject messages from IPs without a valid PTR or with a generic provider PTR.

Trust & reputation

A consistent forward/reverse pair improves your server’s reputation with remote services.

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Configure your reverse DNS

1

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
2

Open your VPS in the control panel

Log in to customer.onetsolutions.net, go to My Services, and select the VPS to manage.
3

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.
4

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.

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Verification

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

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Troubleshooting

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.
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).
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.