How to use rDNS (Reverse DNS)
Posted by , Last modified by on 01 August 2012 02:15 PM

Reverse DNS is another way of fighting spam. It allows other servers to check the authenticity of your server.


You will need to know your IP address.

You can look up your IP address using the ipconfig command within a Windows console:


Make a note of your IP address. If there are multiple IP addresses listed then the first one is the one you need.

Go to and enter your IP address in the RevDNS form on the web page.

It will tell you whether you have a reverse DNS entry.

If you do have a reverse entry, use the name of the reverse entry in the Icewarp hostname field.

e.g. for a reverse name of

Hostname field

You will also need to create a DNS record for pointing to this IP address.

If you do not have a reverse entry, you will need to contact your service provider to have one set up.

Further information about rDNS can be found on internet.

Icewarp can be configured to check other servers for rDNS records. See Security -> Protection in the administrator console.