MySQL server problem – unauthenticated user bug
A couple of months ago, I installed MySQL Workbench 5.2 OSS on my Windows box and used it to monitor my MySQL server that is running on another machine. I noticed that my server status changed from running to stop back and forth frequently, similarly to the following entries in the Startup tab.
2010-03-03 21:06:48 – Server is stopped
2010-03-03 21:06:51 – Server is running
2010-03-03 21:10:28 – Server is stopped
2010-03-03 21:10:31 – Server is running
2010-03-03 21:10:53 – Checked server status: Server is running.
Then I clicked different tabs to check what was going on. I found a lot of entries in the Connection tab look like the following:
Id User Host db Command Time State Info
432 unauthenticated user 66.154.35.193:33207 NULL Connect NULL login NULL
433 unauthenticated user 66.154.35.193:33208 NULL Connect NULL login NULL
434 unauthenticated user 66.154.35.193:33209 NULL Connect NULL login NULL
435 unauthenticated user 66.154.35.193:33210 NULL Connect NULL login NULL
436 unauthenticated user 66.154.35.193:33196 NULL Connect NULL login NULL
I was really upset and confused. My initial thought was my server was under attack. But it was not; the traffic was from my webserver. I googled “mysql unautherticated user login state”. There were a few links shown up. I found useful information from this link (http://bugs.mysql.com/bug.php?id=2814).
The following comment really helped me. I checked etc/hosts on my db server and found there is no reverse DNS setup. You can also find useful information at http://hackmysql.com/dns.
[23 Feb 2005 23:18] Louis Savage
Was able to replicate issue. Only when there was no reverse dns setup or no entry in
/etc/hosts about the remote computers. As soon as this was added the issue stopped.
I went ahead to add entry to the etc/hosts file, something looks like:
192.168.2.XXX webserver name
After I did that, the unaunthenticated user entries in MySQL Workbench 5.2 OSS connection tab disappeared immediately. Magic!
Then I executed the following Linux command at my server.
mysqladmin flush-hosts
Since then, my server works normally and the unwelcome information does not show again.
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