One of the often overlooked aspects of web hosting is reverse DNS. A website will not connect to users who type in a domain name if the forward DNS does not identify the IP address associated with it, but some domains do not have reverse DNS, despite it being an established Internet standard.
Among other uses, reverse DNS can help security-conscious users and professionals verify that the relationship between a domain and an IP address is valid, which helps prevent spam, phishing, and other nefarious activities.
When you manage your server with WHM from cPanel, it is easy to setup reverse DNS records for your IP addresses. Just follow these steps:
Create a reverse DNS zone file
- Login to WHM and navigate to DNS Functions -> Add a DNS Zone
- Type in your IP address (example – 192.168.254.254)
- Enter the reverse DNS name (example -254.128.192.in-addr.arpa). For instructions on adding the appropriate reverse DNS name, see naming an IPv4 zone and naming an IPv6 zone.
Edit the reverse DNS zone file
Now, you will need to create each PTR record.
- From the main WHM page, go to DNS Functions-> Edit DNS Zone
- Under where it says “Add New Entries Below This Line”, enter the corresponding octet or nibble (the final number in the IP address). Example: 254. In the drop down menu, select “PTR”.
- Enter the associated domain name for that IP address
- Repeat for each IP address
To check that your reverse DNS is working, you can type this from the command line:
and the output should look like this:
254.254.168.192.in-addr.arpa domain name pointer www.yourdomain.com
Alternatively, you can find numerous free reverse DNS lookup tools on the web. For more information about setting up reverse DNS in WHM, see the cPanel documentation.