In a split DNS configuration, where separate name servers are used between the external and internal networks, the external name server must be configured to not be reachable from inside resolvers.
An XCCDF Rule
Description
<VulnDiscussion>Instead of having the same set of authoritative name servers serve different types of clients, an enterprise could have two different sets of authoritative name servers. One set, called external name servers, can be located within a DMZ; these would be the only name servers that are accessible to external clients and would serve resource records (RRs) pertaining to hosts with public services (web servers that serve external web pages or provide B2C services, mail servers, etc.) The other set, called internal name servers, is to be located within the firewall and should be configured so it is not reachable from outside and hence provides naming services exclusively to internal clients.</VulnDiscussion><FalsePositives></FalsePositives><FalseNegatives></FalseNegatives><Documentable>false</Documentable><Mitigations></Mitigations><SeverityOverrideGuidance></SeverityOverrideGuidance><PotentialImpacts></PotentialImpacts><ThirdPartyTools></ThirdPartyTools><MitigationControl></MitigationControl><Responsibility></Responsibility><IAControls></IAControls>
- ID
- SV-233869r621666_rule
- Severity
- Medium
- References
- Updated
Remediation - Manual Procedure
1. Navigate to Data Management >> DNS >> Members tab.
2. Select the Grid member identified as running the DNS service and click "Edit".
3. Enable and configure either an Access Control List (ACL) or set of Access Control Entries (ACE).
4. When complete, click "Save & Close" to save the changes and exit the "Properties" screen.
5. Perform a service restart if necessary.