From an internal email (names etc removed):
This problem was created by incorrect network configuration inside the Dodo ISP network. Essentially Dodo received the global Internet table from Telstra then proceeded to advertise this to OPTUS. Since our ISP AARNET receive domestic routes from Optus this caused quite a large asymmetric route of Internet traffic causing connectivity issues. Currently AARNET engineers have disabled peering and route advertisement from Dodo which has resolved the issue however this does prevent connectivity to any sites hosted within Dodo.
Subject: UPDATE: International Routing Issue – 23/Feb/2012 (NOCTTS-6553)Date: 23 February 2012 3:10:13 PM AEDTTo:Cc:SUBJECT: UPDATE: International Routing Issue – 23/Feb/2012SCOPE: International RoutingSTART TIME: Thursday 23 February 2012 14:02 AEDT (Thursday 23 February 2012 03:02 UTC)END TIME: Thursday 23 February 2012 14:34 AEDT (Thursday 23 February 2012 03:34 UTC)MESSAGE 2: International and domestic routing has stabised. AARNet Routing engineers have filtered routing from an upstream provider to resolve the issue. AARNet is monitoring the situation, and does not expect any further issues at this time.DESCRIPTION: International routing is affected due to a domestic commodity partner’s routing issues. AARNet routing engineers are working on the issue at the moment.AFFECTED: International RoutesTICKET NO: NOCTTS-6553CONTACT:COUNTER: Message #2