Google Gmail users inside China have been effectively cut off from access to their accounts for the fourth straight day on Dec. 29.
Google's Transparency Report Website, which provides real-time information on disruptions to Google services worldwide, shows the problems began late Thursday when traffic to the company's Gmail servers for China suddenly plummeted to near zero.
It has remained there since then in what some see as the latest efforts by the Chinese government to disrupt and diminish Google's presence in the country.
Earl Zmijewski, vice president of data analytics at Dyn, an Internet performance monitoring company, said it appears that authorities in China have blocked access to all 29 IP addresses associated with Gmail services in that country.
Google has data centers all around the world that it uses to provide Gmail services to Internet users in different regions. Gmail services to China are provided through servers located in Google data centers in Hong Kong. It is the IP addresses associated with each of those servers that have been blocked, Zmijewski said. By doing so, authorities have effectively cut all access to Gmail for most Internet users in China.
The only way anyone in the country can access Gmail presently is to use a virtual private network (VPN) to navigate to Google's email servers hosted in other countries.
The immediate reason for China's apparent decision to block Gmail access remains unclear, Zmijewski said. But in the past, the country has shown its ability to curtail Internet services quickly if it feels the need, he added.
The latest move continues a pattern that began about six months ago when Chinese authorities first began restricting access to various Google services in the country.
"Prior to the anniversary of Tiananmen [Square] incident, GFW [Great Firewall of China] began to severely disrupt Google search by disrupting TCP connections to Google IPs," GreatFire.org, a site that monitors Internet censorship in China, noted.
Since June, Internet users in China have been unable to access Gmail directly via the Web, though they have been able to do so using third-party email client software. With the latest move to block the IP addresses associated with Gmail, even that access has been eliminated.
"Chinese users now have no way of accessing Gmail behind the [Great Firewall]," GreatFire noted on its site. "Before, they could still send or receive emails via email clients even though Gmail's web interface [was] not accessible."
Google has had problems in China in the past. In 2011 for instance, the company accused the Chinese government of attempting to disrupt its Gmail service by preventing users from sending or reading email messages. At that time, the company described the problems as an attempt at politically driven censorship by the Chinese government.
It has also accused China of hacking into Gmail accounts belonging to Chinese dissidents and of censoring search results there.
Earlier this year, China's state-run media blasted Google and other U.S. technology companies including Facebook and Yahoo for threatening Chinese cyber interests and monitoring the country and stealing its trade secrets.
In an emailed comment, a Google spokesman said the Gmail problems in China were not caused by any technical problems on its end. The Wall Street Journal, meanwhile, Monday quoted a Chinese Foreign Ministry spokeswoman as being unaware of the Gmail access problems in the country. The nation "always welcomes foreign businesses to carry out relevant work in China,” the spokeswoman told the Journal.