Q of Forwarders Statement

[Kevin Darcy]

Hideaki NISHIMURA wrote:

>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.  
>
You can use it for a stub zone too.

- Kevin

>
>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 (^_^)
>
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