Have a couple of things that use netstat in the background. Running 'netstat -b -I en0' in a terminal manually stops it dead in it's tracks when it gets to an IPv6 address. Changing the network DNS from the default router IPs (either IPv6 or IPv4) makes no difference until you change it to point to something outside HughesNet. Using Google's DNS IPs works fine.... so, something currently up with the DNS at HughesNet?
Follow up: Tried rebooting in case the internal DNS was a mess... no joy.
In case anyone is interested, Google's open IPv6 DNS servers are at:
2001:4860:4860::8888
2001:4860:4860::8844
They seem to work just fine.
Follow up #2: Reliability of Google's DNS didn't last long. Gave up after I started to see a whole lot of DNS errors. Back on the HT2200Ws default DNS for now.