一、在上一篇文章中，使用ECS和mysql搭建mysql服务器搭建好了mysql服务器，现在需要远程连接
报错

2003 - Can't connect to MySQL server on '39.106.187.107' (60 "Operation timed out")

1、通过google在stackoverflow.com找到了问题这里写链接内容

2、这个方案貌似可行来试一下

3、说我没有安装nc

[root@iz2ze2llim71y07x3numlbz ~]# nc -l -p 3306
-bash: nc: 未找到命令
[root@iz2ze2llim71y07x3numlbz ~]# nc
-bash: nc: 未找到命令

4、安装一个nc，使用yum安装方便快捷

[root@iz2ze2llim71y07x3numlbz ~]# yum install nc
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
正在解决依赖关系
--> 正在检查事务
---> 软件包 nmap-ncat.x86_64.2.6.40-7.el7 将被 安装 --> 解决依赖关系完成 依赖关系解决

================================================================================
 Package            架构            版本                    源             大小
================================================================================
正在安装:
 nmap-ncat x86_64 2:6.40-7.el7 base 201 k

事务概要 ================================================================================
安装  1 软件包

总下载量：201 k
安装大小：414 k
Is this ok [y/d/N]: y
Downloading packages:
nmap-ncat-6.40-7.el7.x86_64.rpm | 201 kB 00:00 Running transaction check Running transaction test Transaction test succeeded Running transaction 正在安装 : 2:nmap-ncat-6.40-7.el7.x86_64                               1/1 
 验证中 : 2:nmap-ncat-6.40-7.el7.x86_64 1/1 

已安装:
 nmap-ncat.x86_64 2:6.40-7.el7 

完毕！

5、使用nc

[root@iz2ze2llim71y07x3numlbz ~]# nc -l -p 3306
Ncat: bind to :::3306: Address already in use. QUITTING.
[root@iz2ze2llim71y07x3numlbz ~]# 

6、使用nc，访问ip+端口

[root@iz2ze2llim71y07x3numlbz ~]# nc 59.110.218.184 3306
Ncat: Connection timed out.
[root@iz2ze2llim71y07x3numlbz ~]# 

If this is not working, this is not a mysql server configuration issue but a network issue, and you must check your router firewall rules.
Otherwise, your problem comes from mysql server settings. Check your mysql configuration file for bind-address, and remove them to make mysqld accept clients from any IP address.

7、可能是防火墙的问题
进入到/etc/sysconfig，看centos7没有iptables。

8、停止并屏蔽firewalld服务

[root@iz2ze2llim71y07x3numlbz sysconfig]# systemctl stop firewalld
[root@iz2ze2llim71y07x3numlbz sysconfig]# systemctl mask firewalld
Created symlink from /etc/systemd/system/firewalld.service to /dev/null.
[root@iz2ze2llim71y07x3numlbz sysconfig]#

9、安装iptables-services软件包

[root@iz2ze2llim71y07x3numlbz sysconfig]# yum install iptables-services
已加载插件：fastestmirror
Loading mirror speeds from cached hostfile
正在解决依赖关系
--> 正在检查事务
---> 软件包 iptables-services.x86_64.0.1.4.21-18.3.el7_4 将被 安装
--> 正在处理依赖关系 iptables = 1.4.21-18.3.el7_4，它被软件包 iptables-services-1.4.21-18.3.el7_4.x86_64 需要

10、在引导时启用iptables服务

[root@iz2ze2llim71y07x3numlbz sysconfig]# systemctl enable iptables
Created symlink from /etc/systemd/system/basic.target.wants/iptables.service to /usr/lib/systemd/system/iptables.service.

11、启动iptables服务

[root@iz2ze2llim71y07x3numlbz ~]# systemctl start iptables
[root@iz2ze2llim71y07x3numlbz ~]# 

12、保存防火墙规则

[root@iz2ze2llim71y07x3numlbz ~]# service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[  OK  ]
[root@iz2ze2llim71y07x3numlbz ~]# 

另外：管理iptables服务

systemctl [stop|start|restart] iptables

13、编辑防火墙规则，vi /etc/sysconfig/iptables

# Generated by iptables-save v1.4.21 on Mon Mar 26 17:50:59 2018
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [19:3404]
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT -A INPUT -p icmp -j ACCEPT -A INPUT -i lo -j ACCEPT -A INPUT -p tcp -m state --state NEW -m tcp --dport 22 -j ACCEPT -A INPUT -m state --state NEW -m tcp -p tcp --dport 3306 -j ACCEPT -A INPUT -j REJECT --reject-with icmp-host-prohibited -A FORWARD -j REJECT --reject-with icmp-host-prohibited COMMIT
# Completed on Mon Mar 26 17:50:59 2018

14、重启防火墙，systemctl restart iptables