allow-update if in subnet AND key

[Chris Thompson]

If I want to do allow updates to a zone if they use the right TSIG key
AND the update is coming from a specific subnet, what's the slick way
to do this?

  acl bad_nets { ! 10.20.30/24; };

  ...

  allow-update { ! bad_nets; key right_key; };

would work (wouldn't it?) but it seems rather cumbersome..

Am I missing something obvious?

-- 
Chris Thompson
Email: cet1 [at] cam.ac.uk