Where credit is and is not due

Where credit is due:
In light of the “IBB Anonymizer” report, Seth Finkelstein has pointed out that Bennett Haselton had previously discovered that Anonymizer blocks by keyword and that some domains are whitelisted. I was not aware of Bennett’s discovery when I was conducting the research and I have added a note at the bottom of the report acknowledging Bennett’s discoveries.

Where credit is not due:
When things need to be “sexed-up” some (often reporters) will sometimes state that certain websites are blocked in certain countries without actually checking if that information is correct. In this article it is suggested that news.bbc.com is blocked in Iran when no such domain exists and in this article its suggested that “BBC News, MIT and Amnesty International” are blocked in China and Iran.

This is not entirely correct. In fact, BBC (and BBC Persian) MIT, and Amnesty International are accessible in Iran (Checked from TCI/DCI – May, 6 2004). In China, however, these sites are filtered in most locations. A quick test (May, 6 2004) using 34 proxies distributed across 3 networks and a variety of local provincial networks reveals the following:

MIT OK (34/34)
Amnesty OK (2/34)
BBC OK (3/34)

CHINANET (+ Various Provincial Networks)
CNCGROUP (+ Various Provincial Networks)

This is a good example of how complex filtering enumeration is. Not only can those implementing the filtering block (and unblock) web sites at anytime some computerscan access sites that are blocked in other locations. In countries where there is no specific “block page” indicating that you cannot access the requested content, users receive normal network error pages. These errors could indicate that the requested site is blocked — or they could just be normal network errors. When people say “blocked in China” (or Iran) what do they mean? Its quite clear that filtering is being implemented on a variety of (sometimes overlapping) levels of access. It also appears that filtering is being implemented with various levels of control — or competency — in different regions. It is therefore incombent upon those of us making claims about filtering in an entire country do be specific when we state website x is blocked in country x — the details are important.


  1. Just to be sure, no criticism intended – I hope that was clear in my entry.

  2. Absolutely, I just think it’s important to credit Bennett, — its more embarassing on my part as I should been able to find that out in the first place. :)

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