Alasdair wrote:
...
> Could the answer be to disable the IPv6 on NetBSD? If so, how does one do
> this, and does it restrict any other services if you do?
> 
> Regards and thanks for all assistance,
> 
> Alasdair

As opposed to doing anything too drastic you can specify
FETCH_BEFORE_ARGS="-4" in your mk.conf.  This will force ftp(1) to use
IPv4 only.  This should at least help you troubleshoot this a little
further.

adrian.