Ignoring additional records works pretty well for me.
This is harder than it looks. Sometimes the glue A RRs are the only ones you can get -- you need them in order to ask questions in the domain they are in, so without them you have infinite regress. We are planning to store these glue A RRs as query-temporary data shortly, such that they can be used to try to refetch themselves but will never be returned as answers to any other query. Danger, what follows is a request for money. If you expect that to offend you, then hit some key that will delete this message without further ado. Note that the Internet Software Consortium is funded by vendors and ISPs, and that we are currently doing work on INN, BIND, and DHCP. It takes a lot of money to feed all these programmers. If you feel that you are monetarily benefitting from our work on this software, please consider making a donation. (Thanks are due to UUNET for past years' funding, and to Usenix, IBM, and Network Solutions for this year's partial funding.)