对于居住在中国的外国人来说，日常生活中让人感到不满的地方有很多。其中通常包括互联网上网速度、污染和食品安全问题。但近几周，随着上网──特别是访问外国网站和使用虚拟专用网络(VPN)──变得更加困难，互联网成为最主要的问题。VPN使用户可以绕过中国互联网过滤系统。

Reuters造成上述问题的原因有可能是将持续一周的中共十八大。中共十八大是一场照本宣科但至关重要的政治会议，会议闭幕时将公布中共新一代领导人。

中国当局通常会在重大会议和政治敏感日期前后加强对互联网的控制，包括干扰用户对不受中国审查系统限制的外国网站的访问。中国互联网审查系统常被称为“防火长城”(Great Firewall)。但一些用户抱怨在中共十八大召开前夕访问外国网站受到了比平时更多的干扰，一些用户说，他们甚至放弃尝试使用谷歌(Google)的搜索引擎和电子邮件服务。

CloudFlare Inc.的数据证实，中国境内的互联网用户并非只是在凭空臆想。该公司首席执行长普林斯(Matthew Prince)说，该公司的工程师和用户反映，从8月底开始，从中国访问国外网站变得更加困难。该公司为数十万个网站提供网站加速和安全服务。

普林斯还说，屏蔽似乎并不符合任何一种特定的模式，他说中国境内外的网站都遇到了屏蔽的问题。

外国人和少数经验丰富的中国互联网用户通常使用VPN绕过屏蔽访问Facebook和Youtube等西方网站。VPN可以与位于中国境外的服务器建立一个加密链接，进而帮助用户绕过中国互联网过滤系统。不过，近几周，VPN也成为屏蔽的目标，有两家VPN公司对“中国实时报”栏目说，它们注意到屏蔽和干扰的情况增多。

VPN提供商Witopia的发言人说，最近出现的干扰属该公司见过的最严重情况之列。

这位发言人还说，我们从事这一行已经有近八年了，从一开始在中国就有客户。中国政府无疑会时不时地提醒我们他们最终控制着中国境内的互联网，干扰无疑会在政治事件前后有所增多。

他解释说，一个网络的所有者很容易就可以屏蔽、过滤或干扰VPN或任何其他类型的网络访问，无论这个所有者是一个政府还是咖啡店经理。但为了避免将一个网络或国家完全孤立，网络管理者必须留下一些打开的“门”。

他说，鉴于中国的全球化经济和经济增速，它显然不能将自己与全球互联网完全隔离开来，否则其经济将遭受严重损失。可能损失已经出现了。他们似乎只是喜欢提醒每个人，他们是中国境内互联网的老板，他们将以自己的步伐与世界其他地方融合。

不过，尽管VPN和一些网站因敏感的十八大而受到影响，但是除了平时就有的牢骚外，似乎并没有引发新浪(Sina Corp.)微博等中国社交媒体网站用户的太多不满。据分析人士说，这可能表明，政府一直满足于针对广泛的互联网而不是社交媒体。鉴于中国当局过去甘愿采取激进行动来限制社交媒体网站上的讨论，这次的做法让人颇感意外。

单位网(Danwei.com)的创始人、长期关注中国媒体的观察人士金玉米(Jeremy Goldkorn)说，政府可能一直没有对社交媒体进行打击，因为政府目前的审查水平已经很高了。他还说，周三早些时候他在新浪微博上用“国家主席”进行搜索没有得到任何结果。

他说，现在的过滤水平已经到了荒谬的草木皆兵的程度，他们如何把过滤水平再进一步提高呢？

不过，他指出，中国社交媒体公司面临的风险很大。他说，这些公司本周可能安排员工加班，以便确保中国活跃且更加聪明的微博用户不会失去控制。

他说：我敢100%肯定地说，就像其他主要组织一样，所有互联网大公司都接到通知，未来几周它们的平台上不能出现任何麻烦。
For expatriates living in China, the list of gripes that come with facing everyday life is long. Generally among those complaints sit Internet speed, pollution and food safety. But in recent weeks concern about the Internet has taken primacy as access to websites - especially foreign websites and virtual private networks, or VPNs, which allow users to circumvent Chinese Internet filters - has deteriorated.

The likely reason is the weeklong 18th Party Congress, a highly scripted but nevertheless critical political event scheduled to culminate with the unveiling of Communist Party's next generation of leaders.

Chinese authorities routinely move to exert more control over the Internet around big meetings and politically sensitive dates, including by disrupting traffic to foreign websites outside the country's censorship system, commonly referred to as the Great Firewall. But a number of users have complained of unusually frequent disruptions in the run-up to the 18th Party Congress, with some saying they had all but given up trying to use Google's search engine and email service.

Data from CloudFlare Inc., a company that provides web performance and security services for hundreds of thousands of websites, confirms that Internet users inside China are not just imagining things. CloudFlare Chief Executive Matthew Prince said the company's engineers and consumers have reported increased difficulties with traffic out of China beginning at the end of August.

Mr. Prince added that the blocks didn't appear to fit any specific pattern, saying that both foreign sites and domestic Chinese sites experienced blockage problems.

Foreigners and a savvy minority of Chinese Internet users have typically gotten around blocks of Western sites like Facebook and Youtube with VPNs, which form an encrypted link to a server outside of the country, thereby directing traffic around China's Internet filters. But in recent weeks VPNs as well have been targeted, with two separate VPN companies telling China Real Time that they have noticed an uptick in blockages and interferences.

A spokesman for Witopia said the recent disruption is 'one of the most severe' the company had ever seen.

'We've been in this business for almost eight years and have had customers in China since the beginning. The Chinese government definitely reminds us now and again that they ultimately control their part of the Internet, and disruptions definitely increase surrounding political events,' he added.

He explained that it is quite easy for a network owner, be it a government or a coffee shop manager, to block, filter or interfere with VPN protocols or any other type of network traffic. But in order to avoid completely isolating a network or country, the manager of the network must leave some doors open.

'China, with their globalized economy and growth rate, obviously cannot completely isolate themselves from the global Internet or it would exact a significant cost on their economy. It likely already is. They just seem to like to remind everyone that they are the boss of their corner of the Internet and they will integrate with the rest of us at their own pace,' he said.

But while VPNs and a range of websites have suffered due to the sensitivity of the Congress, there doesn't appear to have been many complaints, outside of the normal grumbling, from users of Chinese social media websites like Sina Corp.'s Weibo microblogging platform. That likely indicates the government has been content to target the general Internet and not social media, according to analysts -- a somewhat surprising approach given authorities' willingness to take drastic action to curb discussion on social media sites in the past.

Jeremy Goldkorn, founder of Danwei.com and a longtime observer of Chinese media, said the government has likely not cracked down on social media because its current levels of censorship are already high, adding that he was unable to search for the term 'national chairman' on Sina's Weibo earlier Wednesday.

'When you're looking at that level of filtering, of ridiculous paranoia, how are they going to turn up the dial much more?' he said.

Nonetheless he pointed out that the stakes are high for China's social media companies, who he said likely had employees working overtime this week to ensure China's boisterous and ever clever microbloggers don't get out of hand.

'I would be willing to say, 100% sure, that all the big [Internet] companies are under notice like every other lead organization that no trouble is to emerge on their platform for the next couple of weeks,' he said.