Are 126.com and 163.com fake email addresses?

I'm doing some research on the email addresses that were sent but not deliverer.  I noticed a number of email addresses for our members with the domain 162.com and 163.com.  From what I've been able to tell via limited research, these domains could potentially be fake. Because these email addresses are linked to our members, I would think they would be legitimate. Do you have any information about these domains that you can share?  Thank you.