A domain appears enabled after being added to the Approved List under the IP Filtering section of the management console. However, after a few seconds, its status turns to disabled and the IP Addresses column shows “N/A”.
This occurs in InterScan Messaging Security Suite (IMSS) or InterScan Messaging Security Virtual Appliance (IMSVA).
This occurs because IMSS/IMSVA could not resolve the domain's MX records.
To fix the issue, do either of the following:
- Make sure IMSVA can resolve the MX records of the domain on the Internet.
- Add the IP address to the Approved List instead of the domain name.