Bind 9.7.2+ Extending views with groups

[J. Thomsen]

The view facility is apparently only useful for several copies of the same zone and not for
grouping zones.

If a zone is not present in the first view matching the client, but in another view below,
BIND will apparently return a response of zone not found and not use the next matching view.

As we need a way to administer several groups of zones I was trying to use it for that, but 
this is not possible.

With the rndc addzone/delzone implemented in 9.7.2 with separate view files for the zone
statements, it would be obvious to use this facility for maintaining different groups of
zones within BIND itself and not as now using different include files and external editing
tools. 

My suggestion is that the view concept should be extended to groups including of course
solutions to both resolving and AXFR to slaves. 
User defined names of the .nzf files should also be implemented.

Without much analysis I believe that implementing a search for first matching view
containing the zone should be sufficient.
It is backwards compatible as two views matching the same client currently must be
considered a configuration error.

- Jørgen Thomsen

PS. The ARM on views should be corrected and improved with examples of using keys in the
match-... statements.