How to use rDNS (Reverse DNS)
Posted by Gary, Last modified by on 27 May 2008 06:03 PM
Reverse DNS is another way of fighting spam. It allows other servers to check the authenticity of your server.
2. Make a note of your IP address. If there are multiple IP addresses listed, then the first one is the one you need.
The results beneath will tell you whether you have a reverse DNS entry.
If you do have a reverse entry, use the name of the reverse entry to update the SmartDiscover tab as show in the example below.
Example - for a reverse name of mail.domain.com:
System > Services > SmartDiscover tab
You will also need to create a DNS record for mail.domain.com 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 at: http://www.dnsstuff.com/docs/ptr/
Note: Icewarp can be configured to check other servers for rDNS records. See Mail > Security > DNS tab in the administrator console.