解决PHP无法访问远程mysql的问题
说明，远程服务器是可远程访问的。
我遇到的问题是这样的：有A，B，C三台服务器，C为服务器，B可以用PHP成功连接上C机器的mysql，而A机器则不能连接!
可以说，肯定不是代码有什么问题，服务器上的mysql设置也是没什么问题的，因为B机器都是可以的。
肯定是A机器的设置有问题!
在网上一顿搜，各种说mysql授权问题的，以及修改php.ini的，修改防火墙的，事实上都不是这些问题导致的。
最后想到了SELINUX的问题，对比了下AB两台机器，果然设置不一样!估计就是它的问题，有戏!
进行了如下设置：
root下，用vim打开文件文件/etc/selinux/config
修改SELINUX的值：
#SELINUX=enforcing
SELINUX=disabled
保存并退出。
重启生效，如果不想重启，命令行输入
setenforce 0
回车，OK
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