Primary authoritative name servers must be configured to only receive zone transfer requests from specified secondary name servers.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
medium	V-265983	SRG-APP-000516-DNS-000095	F5BI-DN-300014	SV-265983r1024490_rule	2024-09-09	1

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

ℹ️ Check
If the BIG-IP is transferring zones from another non-BIG-IP DNS server perform the following. From the BIG-IP GUI: 1. DNS. 2. Zones. 3. Zone List. 4. Click on the name of the Zone. 5. Verify "Zone Transfer Clients" >> "Active" column shows only the nameservers that are allowed to request zone transfers. If the BIG-IP appliance is not configured to limit the secondary name servers from which an authoritative name server receives zone transfer requests, this is a finding.

ℹ️ Check

If the BIG-IP is transferring zones from another non-BIG-IP DNS server perform the following. From the BIG-IP GUI: 1. DNS. 2. Zones. 3. Zone List. 4. Click on the name of the Zone. 5. Verify "Zone Transfer Clients" >> "Active" column shows only the nameservers that are allowed to request zone transfers. If the BIG-IP appliance is not configured to limit the secondary name servers from which an authoritative name server receives zone transfer requests, this is a finding.

✔️ Fix
From the BIG-IP GUI: 1. DNS. 2. Zones. 3. Zone List. 4. Click on the Name of the Zone. 5. Move only Nameservers to the "Active" column under "Zone Transfer Clients" that are allowed to request zone transfers. 6. Click "Update".