Microsoft manual ISA Server 2004 Configuration Guide

4.Click on the Forwarders tab. Make sure there is not a checkmark in the Do not use recursion for this domain check box. If this option is selected, the caching-only DNS server cannot use the root hints list of the root Internet DNS server to resolve Internet host names. Select this option only if you decide to use a forwarder. In this case, we do not use a forwarder.

5.Click the Advanced tab. Confirm that there is a checkmark in the Secure cache against pollution check box. This prevents Internet DNS servers and attackers from inserting additional records in a DNS response. These additional records could be used as part of a co-coordinated DNS attack.

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