Q of Forwarders Statement

[Hideaki NISHIMURA]

Thanks, Kevin. :-)

I understand the ARM's syntax miss of forwawrders statement
(we can use empty list).

And your notice about behavior of forwarding in master zone
is very useful.

There is subzones (ex. qux.foo.bar.co.jp) in the lower part
of foo.bar.co.jp zone.  So that, I think it is right to use
forwarders statement with empty list in master zone.

And now, I was able to know forwarders statement could use
not only in master zone (or slave zone) but also in forward
zone.  

Best regards.


  | Hideaki NISHIMURA wrote:
  | 
  | >Hello, bind-users.
  | >
  | >I have two questions about forwarder function (bind-9.3.1).
  | >
  | >first, I set up the forwarders zone as follows (summary).
  | >
  | >    --------------------------------------------------------
  | >    options {
  | >       ...
  | >       forward only;
  | >       forwarders { 192.168.5.1; 172.16.5.1; };
  | >       ...
  | >    };
  | >
  | >    zone "foo.bar.co.jp" {
  | >       type master;
  | >       file "db.foo.bar.co.jp";
  | >       forward only;
  | >       forwarders {};
  | >    };
  | >    --------------------------------------------------------
  | >
  | >  Generally, "forward" and "forwarders" statement use with
  | >  "forward" zone type.
  | >
  | >  But, I want to set up "no forward" in foo.bar.co.jp zone.
  | >  So that, I am setting up these statement with "master"
  | >  zone type.
  | >
  | >  Is this configuration is correct ?
  | >
  | >Second, I read the explanation of zone statement. 
  | >(Bind 9 ARM distributed with bind-9.3.1).
  | >
  | >  In "6.2.23 zone Statement Grammar" section:
  | >
  | >    --------------------------------------------------------
  | >    Zone zone_name [class] [{
  | >      ...
  | >      [ forward (only|first) ; ]
  | >      [ forwarders { ip_addr [port ip_port] ; [ ip_addr [port ip_port] ; ... ] }; ]
  | >      ...
  | >    }];
  | >    --------------------------------------------------------
  | >
  | >    This description means forwarders statement needs a
  | >    least one option ("forwarders { X.X.X.X; };").
  | >
  | >  But, in "6.2.24.1 Zone Types" section, "forward" paragraph:
  | >
  | >    --------------------------------------------------------
  | >    If no forwarders statement is present
  | >      or an empty list for forwarders is given, ...
  | >    --------------------------------------------------------
  | >
  | >    This description means it arrows "forwarders {};".
  | >
  | >  Which is correct ? (arrows least one or empty)
  | >
  | >Best regards.
  | >  
  | >
  | The ARM syntax is wrong. An empty forwarders statement is valid.
  | 
  | Note, however, that an empty forwarders won't prevent forwarding for the 
  | foo.bar.co.jp zone, since there is no forwarding for that zone anyway -- 
  | you're serving it as a master zone, so all of the responses will come 
  | from your own authoritative data. The only effect of the empty 
  | forwarders is to disable forwarding for *subzones* of foo.bar.co.jp. If 
  | you have no subzones of that zone, then there is no need for the empty 
  | forwarders.
  | 
  | - Kevin

--------
Hideaki NISHIMURA (^_^)