aaNet Support Forum

Copy of a message that Jim posted on Whirlpool:

The QLD DNS server cluster (202.76.136.40) will be decommissioned 19-September-2011.

Any customers using manually assigned DNS settings in their modem/router, or server/PCs are advised to check their DNS settings.

For devices/systems that are unable to use dynamically assigned DNS, please use the following settings;

For QLD, and NSW users: Primary DNS 203.24.100.125, Secondary DNS 203.123.69.15

For Vic, WA, SA, NT, and Tas users; Primary DNS 203.24.100.125, Secondary DNS 202.76.170.40

Anyone still using the legacy IP 202.76.136.40 as a DNS server after 18-8-2011 will experience browsing issues.

At the moment they have not actually decommissioned it.
It still functions as a DNS server and returns the same IP address (203.24.100.9) to all requests.
So instead of your system looking up a secondary server, it accepts the wrong IP and will go to this other (aaNet) site which serves a web page telling you to change your settings.
If you weren't web browsing, or were using the proxy then web browsing works and everything else fails silently.