Mysql connection has a large number of unauthenticated user processes

When I was working in the old club, a user suddenly complained that the db was slow. I found the network
The traffic is huge. According to experience, the mysql server may be under attack!
For the current situation, see the attachment:
Www.2cto.com


According to the normal operation, it should be
> Show processlist;
Find a strange connection (process) and kill it!
Www.2cto.com
But I encountered a strange problem during kill, prompting that the process could not be found! After about 10 minutes, the machine will return to normal!
I think a lot of such cases are caused by attacks on the mysql server!
For more information about foreigners, see

A blog on -- skip-name-resolve has a clear explanation: