o memcached module that sits before validator module; checks for memcached
data (on local lan), stores recursion lookup. Provides one cache for multiple resolver machines, coherent reply content in anycast setup.
o no openssl_add_all_algorithms, but only the ones necessary, less space.
+o listen to NOTIFY messages for zones and flush the cache for that zone
+ if received. Useful when also having a stub to that auth server.
+ Needs proper protection, TSIG, in place.
*** Features features, for later
* dTLS, TLS, look to need special port numbers, cert storage, recent libssl.