Wednesday, October 20, 2010

PHP to Remote Database Error: "Can't connect to MySQL server on..."

On a new server migration project I am working on I have separate web and database servers. So, I use a private network to connect them. It took me a day to get working, so I am putting up a post to help others in similar situations.

First, just to clarify, I knew it was a web server problem (and not a network or db permissions issue), because I could connect to the MySQL server just fine from the MySQL command line on the web server. But, when I pinged the PHP web page from my browser I'd get this error:

Can't connect to MySQL server on '' (13)

The problem was SELinux, which was installed and crackin' down on Apache rights.

One simple fix:
setsebool -P httpd_can_network_connect=1

More information can be found in this nice article:

SELinux would allow me to connect from the command line just fine. I could even execute the PHP script from the command line and connect fine. But SELinux did not like it when Apache tried to connect to a computer on the network. Hence the policy update, as stated above.

If you have other issues or it appears that your db server is having issues, here are some other MySQL debug tips as well.

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