Primary authoritative DNS service members must be configured to only receive zone transfer requests from specified secondary DNS service members.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-233871	SRG-APP-000516-DNS-000095	IDNS-8X-400013	SV-233871r1082637_rule	2025-03-11	1

Description
Authoritative name servers (especially primary name servers) must be configured with an allow-transfer access control sub-statement designating the list of hosts from which zone transfer requests can be accepted. These restrictions address the denial-of-service threat and potential exploits from unrestricted dissemination of information about internal resources. Based on the need-to-know, only the secondary name servers need to refresh their zone files periodically. Zone transfer from primary name servers must be restricted to secondary name servers. The zone transfer must be completely disabled in the secondary name servers. The address match list argument for the allow-transfer sub-statement must consist of IP addresses of secondary name servers and stealth secondary name servers.

Description

Authoritative name servers (especially primary name servers) must be configured with an allow-transfer access control sub-statement designating the list of hosts from which zone transfer requests can be accepted. These restrictions address the denial-of-service threat and potential exploits from unrestricted dissemination of information about internal resources. Based on the need-to-know, only the secondary name servers need to refresh their zone files periodically. Zone transfer from primary name servers must be restricted to secondary name servers. The zone transfer must be completely disabled in the secondary name servers. The address match list argument for the allow-transfer sub-statement must consist of IP addresses of secondary name servers and stealth secondary name servers.

ℹ️ Check
Infoblox Grid members do not use DNS zone transfers to exchange DNS data within a single Grid. Communication between Grid members is via a distributed database over a secure Virtual Private Network (VPN). 1. Navigate to the Data Management >> DNS >> Zones tab. 2. Review each zone by clicking "Edit" and inspecting the "DNS service members" tab. 3. Note all external DNS service members, those NOT identified as Type "Grid" (Primary or Secondary). 4. Click the "Zone Transfers" tab. 5. Verify that only the external non-Grid DNS service members identified as DNS service members for the zone or authorized stealth servers are the only systems authorized to perform zone transfers as authorized by a "Named ACL" or "Set of ACEs". 6. When complete, click "Cancel" to exit the "Properties" screen. If Access Controls Lists (ACLs) are not configured for zone transfers to external non-Grid servers, this is a finding.

ℹ️ Check

Infoblox Grid members do not use DNS zone transfers to exchange DNS data within a single Grid. Communication between Grid members is via a distributed database over a secure Virtual Private Network (VPN). 1. Navigate to the Data Management >> DNS >> Zones tab. 2. Review each zone by clicking "Edit" and inspecting the "DNS service members" tab. 3. Note all external DNS service members, those NOT identified as Type "Grid" (Primary or Secondary). 4. Click the "Zone Transfers" tab. 5. Verify that only the external non-Grid DNS service members identified as DNS service members for the zone or authorized stealth servers are the only systems authorized to perform zone transfers as authorized by a "Named ACL" or "Set of ACEs". 6. When complete, click "Cancel" to exit the "Properties" screen. If Access Controls Lists (ACLs) are not configured for zone transfers to external non-Grid servers, this is a finding.

✔️ Fix
1. Navigate to the Data Management >> DNS >> Zones tab. 2. Select the zone and click "Edit". Select the "Zone Transfers" tab and configure access control (ACL or Access Control Entries [ACE]) on each grid member that communicates with an external secondary. 3. When complete, click "Save & Close" to save the changes and exit the "Properties" screen. 4. Perform a service restart if necessary.