[dns-operations] Curiousity, many all numeric sub-domains of .cn?

[Viktor Dukhovni]

Anyone know why there are so many subdomains of ".cn" that are just
lots of digits.  I see around 70,000 such domains.  There are probably
many more.  Sample:

550924988.cn
550928460.cn
550933999.cn
551747442.cn
552218526.cn
552220853.cn
552227094.cn
552229698.cn
552231253.cn
552240774.cn
552246105.cn
553363880.cn
553372226.cn
553383486.cn
553384139.cn
553384147.cn
553391865.cn
553397060.cn
553438133.cn
553700082.cn
553951797.cn
553952941.cn
553956731.cn
553959924.cn

-- 
	Viktor.