Update: Shizhao from Twitter just reported that youtube is now back to normal (Beijing time March 6: 10:40am).
Youtube has been reported blocked in China for two days (March 4-5). According to William Long, netizens failed to access the youtube website since March 4, 8:00pm. The website came back around midnight of March 5, however, according to Shizhao (via twitter), the accessibility only lasted for around 10 mins.
Jeremy Goldkorn from DANWEI pointed out that the access is on and off, not totally blocked (more detailed and update report in the comment section):
The Twitter people are currently talking about Youtube being blocked in China. It's working OK in Beijing though.
Update (JM): Except when it's not: Access has been on again off again today.
According to HerdictWeb report, there were 174 inaccessible reports over the world and 140 came from China:
William Long pointed out that in the past there were occasional temporary blocking of the site: such as Oct 18, 2007 and March 15, 2008 for no clear reason.
This time the blocking coincided with the China's parliament NPC and CPPCC meeting, which is a politically sensitive time. However, Isaac (via twitter) guessed the blocking was caused by the big hit of Grass Mud Horse video in youtube:
i guess http://tinyurl.com/d6rxf7 now in GFW blacklist, causing whole youtube automatically blocked in China after midnight cache flushing
If the blocking is related to reasons above, it would be temporary.
Uptmd records the data transmission error in his blog:
The DNS I am using is 126.96.36.199.
C:\Documents and Settings\Administrator>nslookup www.youtube.com
No problem in ping:
C:\Documents and Settings\Administrator>ping www.youtube.com
Pinging www.youtube.com [188.8.131.52] with 32 bytes of data:
Reply from 184.108.40.206: bytes=32 time=218ms TTL=232
Reply from 220.127.116.11: bytes=32 time=229ms TTL=232
Reply from 18.104.22.168: bytes=32 time=217ms TTL=232
Reply from 22.214.171.124: bytes=32 time=215ms TTL=232
Ping statistics for 126.96.36.199:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 215ms, Maximum = 229ms, Average = 219ms
telnet connection to http:
telnet www.youtube.com 80
HTTP/1.1 500 Server ErrorHttp/1.1 Internal Server Error
Lost contact with the server… GFW is getting stronger and stronger.