V-272380

Discussion

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 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, must be located within the firewall. They must be configured so they are not reachable from outside and therefore provide naming services exclusively to internal clients.

Check Content

If the BIND 9.x name server is not configured for split DNS, this is not applicable.

Verify that the BIND 9.x server is configured to use the "match-clients" sub-statement to limit the reach of the internal view from the external view.

Inspect the "named.conf" file for the following:

view "internal" {
match-clients { <ip_address> | <address_match_list>; };
};

If the "match-clients" sub-statement is missing for the internal view, this is a finding.

If the "match-clients" sub-statement for the internal view does not limit the view to authorized hosts, this is a finding.

If any of the IP addresses defined for the "match-clients" sub-statement in the internal view are assigned to external hosts, this is a finding.