Configuring Reverse DNS in Ruachost

Reverse DNS (rDNS) is the process of mapping an IP address back to a domain name. This is the opposite of standard (forward) DNS, which maps a domain name to an IP address. Reverse DNS is most commonly used for email delivery, as many mail servers check for valid rDNS records before accepting messages.

What is Reverse DNS?

• Forward DNS: Uses A records to map a domain name → IP address.
• Reverse DNS: Uses PTR records to map an IP address → domain name.

Example:

• Forward lookup: example.com → 192.0.2.10
• Reverse lookup: 192.0.2.10 → example.com

Why Reverse DNS Matters

• Email servers: Many providers reject or flag mail as spam if the sending IP does not have a valid PTR record.
• Network troubleshooting: rDNS helps identify hosts by name instead of just IP.
• Security: Provides additional verification of server identity.

Testing Reverse DNS

To check if an IP address has a PTR record:

dig -x xxx.xxx.xxx.xxx

Example:

dig -x 75.98.175.166

Sample output:

166.175.98.75.in-addr.arpa. 42989 IN PTR mail.example.com.

This shows that IP 75.98.175.166 resolves back to mail.example.com.

Configuring Reverse DNS in Ruachost

Shared & Reseller Hosting

• Reverse DNS is already configured for the main server IP.

• If you believe it is missing or incorrect, open a support ticket with ruachost.com and provide:

  • Your domain name
  • Your account’s IP address

VPS & Dedicated Servers

If you have a dedicated IP address:

1. Log in to your ruachost.com Hosting Panel.

2. Open a support ticket under Support.

3. Provide the following details:

   • The IP address you want configured
   • The domain name it should resolve to