All authoritative DNS service members for a zone must be located on different network segments.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-233864	SRG-APP-000516-DNS-000087	IDNS-8X-400006	SV-233864r1082998_rule	2025-03-11	1

Description
Most enterprises have an authoritative primary server and a host of authoritative secondary name servers. It is essential that these authoritative name servers for an enterprise be located on different network segments. This dispersion ensures the availability of an authoritative name server not only in situations in which a particular router or switch fails but also during events involving an attack on an entire network segment. A network administrator may choose to use a "hidden" master authoritative server and only have secondary servers visible on the network. A hidden master authoritative server is an authoritative DNS server in which the IP address does not appear in the name server set for a zone. If the master authoritative name server is "hidden", a secondary authoritative name server may reside on the same network as the hidden master.

Description

Most enterprises have an authoritative primary server and a host of authoritative secondary name servers. It is essential that these authoritative name servers for an enterprise be located on different network segments. This dispersion ensures the availability of an authoritative name server not only in situations in which a particular router or switch fails but also during events involving an attack on an entire network segment. A network administrator may choose to use a "hidden" master authoritative server and only have secondary servers visible on the network. A hidden master authoritative server is an authoritative DNS server in which the IP address does not appear in the name server set for a zone. If the master authoritative name server is "hidden", a secondary authoritative name server may reside on the same network as the hidden master.

ℹ️ Check
Review the DNS configuration to determine all of the DNS service member records for each zone. Based on the NS records for each zone and network architecture, determine the location of each of the DNS service members. 1. Navigate to Data Management >> DNS >> Zones. 2. Select the zone to review. 3. Select the "DNS Name Servers" tab. If all authoritative DNS service members are not located on different network segments, this is a finding.

ℹ️ Check

Review the DNS configuration to determine all of the DNS service member records for each zone. Based on the NS records for each zone and network architecture, determine the location of each of the DNS service members. 1. Navigate to Data Management >> DNS >> Zones. 2. Select the zone to review. 3. Select the "DNS Name Servers" tab. If all authoritative DNS service members are not located on different network segments, this is a finding.

✔️ Fix
1. Navigate to Data Management >> DNS >> Zones. 2. Review zone settings by selecting each zone and reviewing the "DNS Name Server" tab to ensure all DNS service members are located on different network segments.