Sadly the PHP-FPM process on Fedora 22 is forbidden to connect to non-localhost addresses…

So when using a local wordpress installation on a remote MySQL database you will get an SELinux avc, like:

time->Sun Aug 16 14:11:36 2015<br /> type=PROCTITLE msg=audit(1439727096.488:571): proctitle=7068702D66706D3A20706F6F6C20777777<br /> type=SYSCALL msg=audit(1439727096.488:571): arch=c000003e syscall=42 success=no exit=-13 a0=4 a1=55ce39e50cf8 a2=10 a3=0 items=0 ppid=1062 pid=1068 auid=4294967295 uid=48 gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=4294967295 comm="php-fpm" exe="/usr/sbin/php-fpm" subj=system_u:system_r:httpd_t:s0 key=(null)<br /> type=AVC msg=audit(1439727096.488:571): avc: denied { name_connect } for pid=1068 comm="php-fpm" dest=3306 scontext=system_u:system_r:httpd_t:s0 tcontext=system_u:object_r:mysqld_port_t:s0 tclass=tcp_socket permissive=0

You can create a custom SELinux module to allow above violation, see

SELiunx logging.

WordPress, when WP_DEBUG is set to true will show error code „HY000/2002 Permission denied“, in this case, although all config parameters in wp-config.php are correct.