V-272379

Discussion

Authoritative name servers for an enterprise may be configured to receive requests from both external and internal clients. External clients need to receive RRs that pertain only to public services (public web server, mail server, etc.). Internal clients need to receive RRs pertaining to public services as well as internal hosts. The zone information that serves the RRs on both the inside and outside of a firewall must be split into different physical files for these two types of clients (one file for external clients and one file for internal clients).

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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 separate views and address space for internal and external DNS operations when operating in a split configuration.

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

view "internal" {
match-clients { <ip_address> | <address_match_list> };
zone "example.com" {
type Primary;
file "internals.example.com";
};
};
view "external" {
match-clients { <ip_address> | <address_match_list> };
zone "example.com" {
type Primary;
file "externals.db.example.com";
allow-transfer { Secondarys; };
};
};

If the internal and external view statements are configured to use the same zone file, this is a finding.

Inspect the zone file defined in the internal and external view statements.

If any resource record is listed in both the internal and external zone files, this is a finding.