Oh, sorry for the confusion. I read "why only ndt" as "why not ndt".  Strange mistake.

So, answering your actual question now, DONAR only supports NDT at the moment.  We could add more services in the future, if this is a feature we want to support and expand.

And, as to these two names, both show up in the DONAR logs.  Though looking closer again, the most common usage is ndt.iupui.donar.*, ndt.donar.* is very infrequent (less than 100 per day) and only from a single address range.  I think we can skip "ndt.donar".