this.backends.put(Type.A, jgroups);
this.backends.put(Type.AAAA, jgroups);
MXRecord mx = new MXRecord(
new Name("example.com."), DClass.IN, 30,
1, new Name(configuration.getMX()));
this.backends.put(Type.MX, new SimpleBackend("MX", mx));
for (Backend backend : this.backends.values()) {
backend.setCache(cache);
backend.setConfiguration(configuration);
backend.start();