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

# Reverse DNS

Reverse DNS (rDNS) maps an IP address back to a hostname via a PTR record. This is the opposite of a standard DNS lookup — instead of resolving a hostname to an IP, it resolves an IP to a hostname.

## Why Reverse DNS Matters

**Email delivery** — Mail servers commonly verify that a sending server's IP has a valid PTR record matching its hostname. Without rDNS, outbound email is significantly more likely to be rejected or marked as spam.

**Server identification** — Network diagnostic tools such as `traceroute` display PTR records rather than raw IP addresses, making your server identifiable.

## Setting Up Reverse DNS

rDNS is configured directly from the VirtFusion panel.

<Steps>
  <Step title="Access VirtFusion">
    Log in via [Single Sign-On](/vps/virtfusion/logging-in) from the Client Portal.
  </Step>

  <Step title="Select Your VPS">
    Choose your server from the VirtFusion dashboard.
  </Step>

  <Step title="Go to Network Settings">
    Navigate to the network or IP management section of your server.
  </Step>

  <Step title="Set the PTR Record">
    Enter the hostname you want the IP to resolve to (e.g. `mail.example.com`) and save.
  </Step>
</Steps>

<Info>
  Before setting a PTR record, ensure the forward DNS is already configured. The hostname you use for rDNS should have an A record (IPv4) or AAAA record (IPv6) pointing back to the same IP address. Forward and reverse DNS should match.
</Info>

## Verifying Reverse DNS

After saving, verify the PTR record is resolving correctly:

```bash lines theme={"theme":{"light":"light-plus","dark":"ayu-dark"}}
dig -x YOUR_SERVER_IP
```

DNS propagation is typically fast for PTR records but can take up to 24 hours in some cases.

## Forward and Reverse Alignment

For best results — especially for mail servers — forward and reverse DNS should form a consistent loop:

```text theme={"theme":{"light":"light-plus","dark":"ayu-dark"}}
Forward:  mail.example.com  →  A record    →  203.0.113.10
Reverse:  203.0.113.10      →  PTR record  →  mail.example.com
```