named.conf to include zone file and opendkim conf

Question

I would like to separate out opendkim default.txt from zone file and to be include in named.conf instead. I'm a little bit confused on which approach I should use and which is the correct one.

Normal approach:

named.conf

zone "mydomain.com" IN {
  type master;
  file "/var/named/data/mydomain.com.zone";
};

mydomain.com.zone

; zone file for mydomain.com
$ORIGIN mydomain.com.
$TTL 86400
mydomain.com. 86400 IN SOA mydomain.com. soa.mydomain.com. (
  2012010101 ; Serial
  86400      ; Refresh
  7200       ; Retry
  86400      ; Expire
  86400 )    ; TTL
;
mydomain.com. 86400 IN NS ns1.mydnsdomain.com.
mydomain.com. 86400 IN NS ns2.mydnsdomain.com.
mydomain.com. 86400 IN A 1.2.3.4
mydomain.com. 86400 IN MX 0 mydomain.com.
mydomain.com. 86400 IN TXT "v=spf1 a mx ?all"
www 86400 IN CNAME mydomain.com.
ns1 86400 IN A 1.2.3.4
ns2 86400 IN A 1.2.3.4
default._domainkey     IN      TXT     ( "v=DKIM1; k=rsa; "
    "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2VtDlIkIZXHbt5f6fFlwB2bVfYkFI44WvIx+Xx0/oqlxCAaKCkHmlYrLkqamuI/Flm51U/Yht5z1CEbQs/YdVXXkryROGuN4+5G5TR89x4zd7RX+SqODYqeYlrG5V1fQM1WFS42ei9zlDmslK7JJrlOQrs8jYbvQoV39cQuIUNwIDAQAB" )  ; ----- DKIM key default for mydomain.com

1st approach:

named.conf

zone "mydomain.com" IN {
  type master;
  file "/var/named/data/mydomain.com.zone";
  file "/etc/opendkim/keys/mydomain.com/default.txt";
};

mydomain.com.zone

; zone file for mydomain.com
$ORIGIN mydomain.com.
$TTL 86400
mydomain.com. 86400 IN SOA mydomain.com. soa.mydomain.com. (
  2012010101 ; Serial
  86400      ; Refresh
  7200       ; Retry
  86400      ; Expire
  86400 )    ; TTL
;
mydomain.com. 86400 IN NS ns1.mydnsdomain.com.
mydomain.com. 86400 IN NS ns2.mydnsdomain.com.
mydomain.com. 86400 IN A 1.2.3.4
mydomain.com. 86400 IN MX 0 mydomain.com.
mydomain.com. 86400 IN TXT "v=spf1 a mx ?all"
www 86400 IN CNAME mydomain.com.
ns1 86400 IN A 1.2.3.4
ns2 86400 IN A 1.2.3.4

default.txt

  default._domainkey     IN      TXT     ( "v=DKIM1; k=rsa; "
      "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2VtDlIkIZXHbt5f6fFlwB2bVfYkFI44WvIx+Xx0/oqlxCAaKCkHmlYrLkqamuI/Flm51U/Yht5z1CEbQs/YdVXXkryROGuN4+5G5TR89x4zd7RX+SqODYqeYlrG5V1fQM1WFS42ei9zlDmslK7JJrlOQrs8jYbvQoV39cQuIUNwIDAQAB" )  ; ----- DKIM key default for mydomain.com

2nd approach:

named.conf

zone "mydomain.com" IN {
  type master;
  file "/var/named/data/mydomain.com.zone";
};

mydomain.com.zone

; zone file for mydomain.com
$ORIGIN mydomain.com.
$INCLUDE "/etc/opendkim/keys/mydomain.com/default.txt" <-- guessing
$TTL 86400
mydomain.com. 86400 IN SOA mydomain.com. soa.mydomain.com. (
  2012010101 ; Serial
  86400      ; Refresh
  7200       ; Retry
  86400      ; Expire
  86400 )    ; TTL
;
mydomain.com. 86400 IN NS ns1.mydnsdomain.com.
mydomain.com. 86400 IN NS ns2.mydnsdomain.com.
mydomain.com. 86400 IN A 1.2.3.4
mydomain.com. 86400 IN MX 0 mydomain.com.
mydomain.com. 86400 IN TXT "v=spf1 a mx ?all"
www 86400 IN CNAME mydomain.com.
ns1 86400 IN A 1.2.3.4
ns2 86400 IN A 1.2.3.4

default.txt

  default._domainkey     IN      TXT     ( "v=DKIM1; k=rsa; "
      "p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC2VtDlIkIZXHbt5f6fFlwB2bVfYkFI44WvIx+Xx0/oqlxCAaKCkHmlYrLkqamuI/Flm51U/Yht5z1CEbQs/YdVXXkryROGuN4+5G5TR89x4zd7RX+SqODYqeYlrG5V1fQM1WFS42ei9zlDmslK7JJrlOQrs8jYbvQoV39cQuIUNwIDAQAB" )  ; ----- DKIM key default for mydomain.com

Or is there any better way to do this instead of just including the defaul.txt content in the domain zone file?

Thanks!

Answer 1

The second approach is the correct way to use include files. I'm pretty sure that multiple file lines within a zone declaration (i.e. your first example) will end up generating an error.

Be advised:

• If your named process is operating in a chrooted setup, the absolute path in the $INCLUDE will need to be relative to the chroot. (like existing zone files)
• When secondary servers perform a zone transfer, they will see the combined contents of the zone file. The $ directives only effect how the file is loaded into memory for the current server; when the zone transfer is requested, the zone as it's loaded into memory is what gets transferred.