dstiles - 10:31 pm on Jan 31, 2013 (gmt 0)
I use dig on linux, run in a bash shell script. I run the checks against one of the relevant DNS servers (eg yandex for yandex, ms for bingbot etc).
Slow but a) I'm in no hurry for the results and b) I worry that a fast DNS scan would get me blocked.
Not sure how to run this under windows but there is probably an equivalent to dig.