SQLSTATE[HY000] [2003] Can’t connect to MySQL server on ‘xxx.xxx.xxx.xxx’ (13)

One of the things I wish I had found in Google faster when trying to figure out why PHP script refuses to connect to remote MySQL server issuing an error SQLSTATE[HY000] [2003] Can't connect to MySQL server on 'xxx.xxxx.xxx.xxx' (13) I am able to connect from local shell, so first thought was if something wrong with recent Zend Framework upgrade, but after a while I figured out that answer is very simple – SELinux was blocking remote connections from PHP scripts executed by Apache web server. The error code (13) at the end of error message means “permission denied”, so that’s...