Bind Zone Files

BIND zone files come in two categories: forward zones (located in /var/named/primary/*) and reverse zones (located in /var/named/reverse/*).

Note that this format, standardized in RFC 1035, has been widely adopted outside of the BIND project.

Forward Zone

To check the configuration of the forward zone file for example.com, run...

named-checkzone -d example.com /var/named/primary/example.com

Example

This is a forward zone file for example.com.

$TTL 1D
@             IN      SOA       host1.example.com.  me.example.com.  (
                                10             ; Serial
                                8H             ; Refresh
                                2H             ; Retry
                                4W             ; Expire
                                1D )           ; Minimum
;
              IN      NS       host1
              IN      MX  10   host1
;
example.com.  IN      A        192.168.1.1
host1         IN      A        192.168.1.1
www           IN      CNAME    host1
ftp           IN      CNAME    host1
;
host2         IN      A        192.168.1.201
host3         IN      A        192.168.1.202

Structure

The first column is the fully qualified domain name (FQDN). If this column is omitted, the last-defined FQDN is implicitly referenced.

The second and third columns are the record type. The second column is almost always Internet (IN).

Start of Authority

This line indicates that host1.example.com is the Start of Authority (SOA) for the zone, and that [email protected] is the technical contact. @ is a macro for the fully qualified domain name, defined in the bind(8) configuration.

@             IN      SOA       host1.example.com. me.example.com. 

Note the period is mandatory to indicate that they are FQDNs.

Name Server

This line indicates that the previously-defined FQDN is also the Name Server (NS) for this zone.

              IN      NS       host1

Mail Exchange

This line indicates that the previously-defined FQDN is also hosting a mail server (or Mail Exchange) (MX). It should be defined with a priority; here that is set to 10.

              IN      MX  10   galaxy

There are additional considerations for public MX records; see here for details.

Address

To define the address for a domain name, use Address (A) records.

example.com.  IN      A        192.168.1.1
host1         IN      A        192.168.1.1

As with the SOA record, trailing periods are required to indicate a FQDN.

After this line, host1 can be referenced as an address.

www           IN      CNAME    host1

Reverse Zone

To check the configuration of the reverse zone file for 192.168.1.0/24, run...

named-checkzone -d 1.168.192.in-addr.arpa /var/named/reverse/192.168.1

Example

This is a reverse zone file for 192.168.1.0/24.

$TTL 1D
@             IN      SOA       host1.example.com.  me.example.com.  (
                                10             ; Serial
                                8H             ; Refresh
                                2H             ; Retry
                                4W             ; Expire
                                1D )           ; Minimum
;
              IN      NS        host1.example.com.
1             IN      PTR       host1.example.com.
;
201           IN      PTR       host2.example.com.     ; IP address for 'host2'
202           IN      PTR       host3.example.com.     ; IP address for 'host3'

CategoryRicottone