ZoneAlarm customers have complained that access to the internet was denied after installing a patch designed by Microsoft to fix a vulnerability in both the client and server Domain Name System (DNS) packages within Windows. The issue is with Microsoft Update KB951748 (MS08-037), which addresses a DNS flaw.

ZoneAlarm customers who have automatic update selected for Windows Update, and whose ZoneAlarm internet-security level is set to 'high', will experience a loss of internet connectivity upon reboot.

ZoneAlarm users without automatic update may wish to wait to install the update until the matter is resolved.

For those who have already installed the patch, Check Point recommended removing Microsoft Update KB951748 from their systems. Detailed instructions for doing this can be found on the ZoneAlarm website. Another option is to lower the ZoneAlarm internet-security setting to 'medium', although Check Point said it does not recommend that measure.

Workaround to Sudden Loss of Internet Access Problem