IPv4 vs IPv6 name resolution

[Chris Ross <cross+netbsd%distal.com@localhost>]

  Hi there.  I have an active and working IPv6 connection.  This  
solves most of my problems, but for some unknown reason, I frequently  
have problems using ftp://ftp.nluug.nl/ for pkgsrc source retrieval.   
For whatever reason, if I'm using IPv6, the transfers never start  
(using extended passive mode).  This may well be an error on my end,  
but most other IPv6 connectivity works without issue, so I'm not  
inclined to investigate it too much.

  My question is this:  There used to be an environmental variable  
that caused the resolver to prefer one family over another.  I wasn't  
able to find it with quick man page searching.  Is there a way, other  
than by turning off IPv6 on the host, to cause standard utilities  
(like ftp) to resolve names to IPv4 addresses before IPv6 addresses?

  Thanks...

                    - Chris