richard1088:
I am using internet.telecom.co.nz, and it assigns a routable IP address.
This still does not seem like a network issue. If Telecom were dropping ACKS, why would they not drop ACKS from me when I am calling other, non "08xx" numbers?
From the horse's mouth: http://www.geekzone.co.nz/NealR/6460
"internet.telecom.co.nz: Internet access with fire walling to block unsolicited traffic from Internet."
"direct.telecom.co.nz: Allows uninitiated traffic from the Internet."
You should at least try it - perhaps fix the issue maverick is pointing out?
Also, as a reminder to EVERYONE. Always give all the information, regardless of what you think is important or not. Even your provider is important. Even the colour of your shirt while doing the tests.