Offline filtering preferred way of Web censorship

With its value-for-money proposition compared with alternatives, offline URL filtering favored by Internet service providers to enable Web filtering in accordance to government regulation, says security exec.

For countries looking to censor the Web, offline URL filtering appear to be the weapon of choice as more Internet service providers (ISPs) turn to it to comply with government regulations in a cost-effective manner.

According to Eric Chan, regional technical manager of Fortinet Southeast Asia and Hong Kong, offline URL filtering provides Web content filtering capabilities and manageability at "only a fraction of the price" of a full-fledged URL filtering product. It is also more effective than other filtering techniques via DNS (domain name system) or Internet Protocol (IP), he noted in his e-mail.

Elaborating, Chan told ZDNet Asia that while DNS filtering is cheap and easy to implement as ISPs need only to make "minor changes" to existing DNS servers, it is easy to circumvent and unable to block sub-sections of Web sites. For example, using DNS filtering to block one YouTube video will mean blocking the entire site, the executive explained.

As for IP filtering, the pros are similar to DNS filtering but the cons include incurring additional load and processing overhead on ISPs' existing routers and firewalls, Chan noted. Additionally, DNS filtering is difficult to maintain and manage, and determined Web users will still be able to bypass the virtual blockade through Internet proxies and VPNs (virtual private networks), he added.

On the other end of the cost scale, a full-fledged URL filtering system will support both manual and dynamic categorization of sites that need to be blocked such as pornography, child abuse or spyware, he said. However, it is also a more costly choice for many ISPs to implement, he pointed out.

That presents offline URL filtering as the best option for ISPs that need to conform to government regulations to censor the Internet, Chan said. The system performs URL filtering on Web traffic "destined" to arrive at a filtered Web site, and this can be determined based on the destination's IP address, he explained.

"There are many ISPs in the world using offline URL filtering to meet regulators' mandates," the executive revealed.

The caveat, though, is whether governance regarding Web censorship is stringent or not.

According to Chan, ISPs view the deployment of Internet filtering to meet censorship requirements as additional infrastructure cost that yield little or no revenue return. So unless there is strict governance, "most ISPs will use the simplest and cheapest solution", and this typically leads to DNS filtering, he said.

"National interest" drives censorship
Within the Asia-Pacific region, Internet filtering is usually initiated out of the need to "protect national interest", where the censorship of anti-nationalistic and political Web sites is "common" in this part of the world, Chan noted.

He also identified piracy and copyright-violating Web sites such as file-sharing or peer-to-peer sites as emerging hotspots for Web censorship in the region.

However, two Asian economies ZDNet Asia spoke to rejected the notion of Web censorship.

A spokesperson for Hong Kong's Office of the Government Chief Information Officer (OGCIO) noted that for ICT development, the "free flow" of information with no censorship on content transmission "provides a good environment" for the development of online and Internet-based businesses. The Internet is also an important tool for the community to utilize for a wide variety of "economic, social and personal purposes", he added.

"It is the government's long-standing policy to safeguard the freedom of expression and freedom of speech, and to preserve the free flow of information," the spokesperson stated in an e-mail.

Similarly, a spokesperson from the Malaysian Communications and Multimedia Commission (MCMC) said the country does not mandate Internet filtering and has "no plans" to do so.

That said, there are exceptions to that stance, the government agency said.

"Any action taken by the MCMC to request ISPs to block Web sites is based on an evaluation made on a case-by-case basis and pursuant to Section 263(2) of the Communications and Multimedia Act 1998, which imposes an obligation on licensees including ISPs to assist the Commission or other authority to prevent the commission or attempted commission of an offence under any written law of Malaysia," it said.

Not-so-open World Wide Web
Both governments were responding to reports of countries actively looking to censor the Web.

Iran, for example, is creating a "national Internet" for its citizens. According to a Wall Street Journal report in May, the country's director of the telecommunication ministry's research institute, Reza Bagheri Asl, said 60 percent of the nation's homes and businesses would soon be on the new, internal network. Within two years, it would extend to the entire country, he added.

A separate article by the New York Times, also in May, reported that Turkish citizens had protested against Internet filtering regulations imposed by the country's Information and Communications Technologies Authority, also known by its Turkish initials as B.T.K. It stated that ISPs, beginning in August, would have to offer consumers four filtering-tiers which would limit access to several sites.

The new regulation also caught the attention of hacktivist group, Anonymous, which initiated in June a denial-of-service attack to take down the official site of Turkey's Telecommunications Communication Presidency as a sign of protest.

The B.T.K. did not reply to ZDNet Asia's queries.

The uproar from Turkish civilians should not come as a surprise, though, said Chan. He cited public opinion and backlash from the online community as "major concerns" for governments thinking of or that have implemented Internet filtering.

"While there are legitimate grounds for censorship, for example over morality issues, the act is still perceived by many as a restriction on the freedom of speech," he surmised.