Story : https://www.eff.org/deeplinks/2013/04/australian-networks-censor-community-educa
EFF has long opposed Australia's Internet censorship schemes, warning that even the voluntary filtering that has been implemented by Australia's largest ISPs, Telstra and Optus, lacks transparency and accountability, and could lead to collateral damage--accidental censorship of websites that are not violating the law in any way. A dramatic example of such collateral damage appears to be occuring at the moment.
EFF was recently contacted by the organisers of a community group called the Melbourne Free University (MFU) because their site appears to have been blocked or censored by Australian network operators, possibly at the request of the Australian government. Users from some (but not all) Australian ISPs have been unable to reach the Melbourne Free University site since Thursday the 4th of April. An employee of one of the affected ISPs told MFU by email that the site was blocked as a result of an order from the Australian government, but was unable to say more. Research by EFF and MFU, and discussion amongst Australian network operators, confirms that the IP address has been black holed by a number of Australian ISPs, preventing access to more than 1,200 websites including the Melbourne Free University (multiple websites sharing a single IP address is common due to virtual hosting).
The causes for the block are currently unknown. Speculation by the Australian networking community has included criminal investigations, action by ASIC, or DDOS mitigation. Unusually, a representative of one of the blackholing ISPs, AAPT, would only state that "in regard to this issue, this IP address has been blocked". Under conditions where the cause was to protect the functioning of the Internet, such as to combat a denial-of-service attack, one would expect the ISP to clearly describe the reasons for the temporary filter to better assist other network operators. It would be surprising if the cause was Australia's nascent Internet censorship system as that is reported to operate with DNS rather than IP blocks.