MySQL Flooded by "unauthenticated user"

MySQL & MariaDB Other MySQL® Questions
1

Hi Gurus,

My MySQL server was very busy. After checking, I found many unauthenticated user connections when running “show full processlist”:

| 2018434580 | unauthenticated user | connecting host | NULL | Connect | NULL | login | NULL | 0 | 0 |
| 2018434583 | unauthenticated user | :9395 | NULL | Connect | NULL | Reading from net | NULL | 0 | 0 |
| 2018434586 | unauthenticated user | connecting host | NULL | Connect | NULL | login | NULL | 0 | 0 |
| 2018434592 | unauthenticated user | connecting host | NULL | Connect | NULL | login | NULL | 0 | 0 |
| 2018434595 | unauthenticated user | connecting host | NULL | Connect | NULL | login | NULL | 0 | 0 |
| 2018434598 | unauthenticated user | connecting host | NULL | Connect | NULL | login | NULL | 0 | 0 |

I searched the internet and it said that this was related to the DNS problem. To fix this problem, simply start the mysql server with skip-name-resolve variable in my.cnf. However, I already set this variable in my.cnf and it still happening.

mysql> show variables like ‘skip_name_resolve’;
±------------------±------+
| Variable_name | Value |
±------------------±------+
| skip_name_resolve | ON |
±------------------±------+
1 row in set (0.10 sec)

Can anybody have met the same situation and give me some advice? My MySQL database version is 5.6.19-67.0

Thanks much!

Tony

2

Hi Jardenblack26;

If you’re getting a lot of them, and using SSL, it might also be SSL authentication related. So I would try disabling SSL to see if that helps. Then if that’s the problem, you’ll have to troubleshoot the root of the issue.

-Scott