网络屏蔽的概念已经存在了相当长的一段时间，许多国家都在使用这种做法。但它究竟意味着什么，普通网民又该如何避免呢？
什么是网络屏蔽？
Web blocking is a practice that is present in a lot of countries, and it includes various techniques that these countries’ ISPs (Internet Service Providers) are using to limit their users’ reach online. By using a combination of data feeds by various companies dedicated to content control, as well as that of government agencies, and forced by court orders, ISPs are basically blocking various websites and content that is available online.
封堵网站的原因有很多，各国的情况也不尽相同。通常情况下，被屏蔽的内容包括色情、受版权保护的内容、恶意网站、互联网服务提供商默认引入的过滤器、教育内容（在某些情况下）、企业内容、技术威胁、极端主义材料、被政府列入黑名单的网站等。包含种族和宗教仇恨内容的网站以及各种黑客网站等也被删除。
To block and filter these websites, the ISPs and the government agencies use a wide range of methods. Those include IP address blocking, DNS hijacking and/or blocking, as well as Deep packet inspections.
当然，封杀内容是一个非常有争议和复杂的问题。拒绝访问网上内容可能会被争取自由的组织视为侵犯用户的数字权利。然而，即使是这些组织也看到了屏蔽可能直接伤害用户或导致伤害他人的危险材料和恶意网站的潜在好处。
更不用说其他一些重要问题了，比如儿童的性化问题，这些问题迫使很多人改变了对网络屏蔽的看法，开始从更有利的角度来看待它。
然而，互联网的发展已经找到了应对这些屏蔽和过滤的方法，现在几乎任何人，无论是否精通技术，都可以绕过这些屏蔽和过滤。
如何自由访问网络？
As mentioned, there are a lot of countries around the world that are practising web blocking, with only a handful of them that are not. Some of these countries are blocking only what is deemed necessary for the protection of the users. Others, however, have started doing it for different purposes too. The concept has even led to repression of information in some extreme cases, like North Korea, and alike.
时至今日，英国仍然是最发达的国家之一，仍然非常支持网络屏蔽，有些人认为他们使用这一功能的程度远远超出了需要。此外，英国不仅禁止本国公民访问各种网站，而且还实行外部屏蔽，即很多内容只对本国公民开放。
Still, the internet consists of many talented individuals that have developed various methods of bypassing the blocks, and those include different tools that are available online. Things like proxies, VPNs, and anonymous browsers like Tor started popping up all over the internet in the last decade.
These are the tools that allow users to hide or change their IP address in order to confuse the ISP’s systems regarding their locations. The IP address blocking has a pretty similar concept. Various websites are blocked by the ISPs, but only for those IP addresses that they themselves are issuing. If the user connects to a server in a country that is not blocking a specific website, they will be given a new IP address, one that has access to that specific website.
That way, the block is bypassed, and the users will be granted access to the content blocked by their own ISP. Proxies work in a slightly different way, and most of them will only hide the user’s real IP. They also come as a more economical option, but VPNs are much safer to use since they provide a much larger level of privacy and online anonymity. Not to mention that most of the good ones do not record users’ browsing history, and even if they do, they are not connecting it to the specific user, but are instead using it to better their technology.
当然，用户在使用这项技术时需要小心谨慎，最好不要使用免费服务，因为它们可能会将这些浏览历史记录出售给第三方。
至于像 Tor 这样的匿名浏览器，它们也是不错的选择，但也有自己的局限性。Tor 最大的问题是数据流速度慢，因此几乎无法通过该浏览器下载内容或观看视频。尽管如此，Tor 也有很多优点，其中之一就是它可以访问深层网络，并能保证用户信息的私密性。
Methods of bypassing blocks and accessing the full potential of the internet are many, but the users need to remember that caution is always the top priority. The use of these methods is not illegal, but it is frowned upon in many countries, which might lead to government agencies contacting the VPN providers and asking for your information if you are detected as a VPN user. Some VPNs reserve the right to provide that info if asked to do so, so keep that in mind as well.
