mysql 连接报错 2013 连接mysql2003错误

MySQL远程连接失败(错误码:2003)

更新于2018年3月12日

一 环境信息

• 服务器系统：Oracle Linux 7.3
• 服务器MySQL版本：MySQL 5.7.20
• 本地系统：win10
• 本地客户端：Navicat for MySQL 10.1.7
• 本地开发环境：python(3.6.3)，PyMySQL(0.8.0)
• 假设：登录用户名为admin，密码为adminpwd ，MySQL连接端口3306

二 问题描述

• 本地客户端及代码连接均失败： 2003, "Can't connect to MySQL server on '192.168.1.166' (10061)"
• python连接MySQL代码

import pymysql
conn= pymysql.connect(
         host='192.168.1.166',
         port = 3306,
         user='admin',
         passwd='adminpwd',
         db ='test',
         charset='utf8'
         )
# 使用cursor方法获取操作游标
cur = conn.cursor()
# 使用execute 方法执行sql语句
cur.execute("select version()")
# 使用fetchone()方法获取一条数据库
data = cur.fetchone()
print("datebase version : %s"%data)
# 关闭数据库连接
conn.close()
import pymysql
conn= pymysql.connect(
         host='192.168.1.166',
         port = 3306,
         user='admin',
         passwd='adminpwd',
         db ='test',
         charset='utf8'
         )
# 使用cursor方法获取操作游标
cur = conn.cursor()
# 使用execute 方法执行sql语句
cur.execute("select version()")
# 使用fetchone()方法获取一条数据库
data = cur.fetchone()
print("datebase version : %s"%data)
# 关闭数据库连接
conn.close()

• python连接MySQL报错

Traceback (most recent call last):    
File "D:/JetBrains/test/study_test/mysql_test1.py", line 15, in <module>
 charset='utf8'
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\__init__.py", line 90, in Connect
 return Connection(*args, **kwargs)
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\connections.py", line 699, in __init__
 self.connect()
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\connections.py", line 967, in connect
 raise exc
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on '192.168.1.166' (timed out)")         
Traceback (most recent call last):    
File "D:/JetBrains/test/study_test/mysql_test1.py", line 15, in <module>
 charset='utf8'
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\__init__.py", line 90, in Connect
 return Connection(*args, **kwargs)
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\connections.py", line 699, in __init__
 self.connect()
File "D:\JetBrains\pyEnv\python363\lib\site-packages\pymysql\connections.py", line 967, in connect
 raise exc
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on '192.168.1.166' (timed out)")

三 官方文档描述

"The error (2003) Can't connect to MySQL server on 'server' (10061) indicates that the network connection has been refused. You should check that there is a MySQL server running, that it has network connections enabled, and that the network port you specified is the one configured on the server."
    金山译文：错误(2003年)无法连接到“server”(10061)上的mysql服务器，表示网络连接已被拒绝。您应该检查是否有一个mysql服务器正在运行，它是否启用了网络连接，并且您指定的网络端口是在服务器上配置的。

四 解决过程

• （1） Xshell远程登陆服务器，用“ps aux|grep mysql”命令查看，MySQL服务已启动:
• （2） 用"vim my.cnf"命令查看my.cnf文件(在MySQL安装目录下，我的位置是/usr/local/mysql/my.cnf),修改其对应的值并重启MySQL。对应内容如下：

[mysqld]
bind-address = 0.0.0.0  # 表示允许任何主机登陆MySQL
port=3306               # 表示MySQL运行端口为3306
[mysqld]
bind-address = 0.0.0.0  # 表示允许任何主机登陆MySQL
port=3306               # 表示MySQL运行端口为3306

• （3）用“mysql -u admin -p”命令，回车后输入密码“adminpsw”能正常登陆服务器MySQL

mysql> show global variables like 'port';  # 查看MySQL运行的实际端口
+---------------+-------
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.01 sec)
mysql> show global variables like 'port';  # 查看MySQL运行的实际端口
+---------------+-------
| Variable_name | Value |
+---------------+-------+
| port          | 3306  |
+---------------+-------+
1 row in set (0.01 sec)

mysql> use mysql;
  Reading table information for completion of table and column names
  You can turn off this feature to get a quicker startup with -A
  
  Database changed
  mysql> select host,user from user;
  +-----------+---------------+
  | host      | user          |
  +-----------+---------------+
  | %         | admin         |
  | %         | root          |
  | localhost | mysql.session |
  | localhost | mysql.sys     |
  +-----------+---------------+
  5 rows in set (0.00 sec)
  mysql> use mysql;
  Reading table information for completion of table and column names
  You can turn off this feature to get a quicker startup with -A
  
  Database changed
  mysql> select host,user from user;
  +-----------+---------------+
  | host      | user          |
  +-----------+---------------+
  | %         | admin         |
  | %         | root          |
  | localhost | mysql.session |
  | localhost | mysql.sys     |
  +-----------+---------------+
  5 rows in set (0.00 sec)

# 如果上述查询结果，admin用户对应的host不为%，则修改用户权限
  # 此处需注意的是，修改权限时要带上密码(IDENTIFIED BY 'adminpwd'),虽然不知道具体原理，但是没加密码之前客户端还是不能远程访问MySQL。

mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' IDENTIFIED BY 'adminpwd' WITH GRANT OPTION; 
  Query OK, 0 rows affected, 1 warning (0.00 sec)

  mysql> FLUSH PRIVILEGES;
  Query OK, 0 rows affected (0.00 sec)

  mysql> GRANT ALL PRIVILEGES ON *.* TO 'admin'@'%' IDENTIFIED BY 'adminpwd' WITH GRANT OPTION; 
  Query OK, 0 rows affected, 1 warning (0.00 sec)

  mysql> FLUSH PRIVILEGES;
  Query OK, 0 rows affected (0.00 sec)

• （4） 至此，我的本地Navicat客户端已经能都正常访问服务器端，但是运行上述python连接MySQL代码还是报一样的错误。
• （5）查网上资料说可能是防火墙屏蔽了3306端口，本地cmd"ping 192.168.1.166"能够Ping通，再用”telnet 192.168.1.166 3306“命令检查端口是否被屏蔽，结果为"正在连接192.168.1.166...无法打开到主机的连接。 在端口 3306: 连接失败",说明是防火墙的问题
  （如果Win10 telnet不是内部或外部命令，决解方法参考连接：https://jingyan.baidu.com/article/1e5468f9033a71484961b7d7.html）
• （6） 起初我以为是指我本地防火墙的问题，于是把本地防火墙关了，结果问题并没有解决。
• （7） 其实应该是远程服务器的防火墙问题。远程登陆服务器（我用root用户登录的），检查防火墙状态

systemctl start firewalld # 开启防火墙
systemctl stop firewalld  # 关闭防火墙
systemctl status firewalld  #检查防火墙状态

• （8） 关闭远端服务器防火墙后，运行本地运行本地python连接MySQL代码，MySQL连接成功

[root@db sysconfig]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: active (running) since 三 2018-02-28 17:18:10 CST; 7s ago
     Docs: man:firewalld(1)
 Main PID: 5452 (firewalld)
   CGroup: /system.slice/firewalld.service
           └─5452 /usr/bin/python -Es /usr/sbin/firewalld --nofork --nopid
[root@db sysconfig]# systemctl stop firewalld
[root@db sysconfig]# systemctl status firewalld
● firewalld.service - firewalld - dynamic firewall daemon
   Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled)
   Active: inactive (dead)
     Docs: man:firewalld(1)

• （9）如果你觉得关闭防火墙不安全，可打开远端服务器的iptables（安装或升级命令“yum install iptables”）（我用root用户登录的），并用“vi /etc/sysconfig/iptables”检查3306端口是否打开，如没有，在文件中加入“-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT”（如下所示），保存文件并用“service iptables restart”命令重启iptables

# Generated by iptables-save v1.4.21 on Wed Feb 28 12:19:33 2018
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [34:3136]
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT    ## 加上此行
-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 -j REJECT --reject-with icmp-host-prohibite
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Wed Feb 28 12:19:33 2018
~                                                                                                  
~                                                                                                       
"/etc/sysconfig/iptables" 17L, 654C
# Generated by iptables-save v1.4.21 on Wed Feb 28 12:19:33 2018
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [34:3136]
-A INPUT -p tcp -m tcp --dport 3306 -j ACCEPT    ## 加上此行
-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 -j REJECT --reject-with icmp-host-prohibite
-A FORWARD -j REJECT --reject-with icmp-host-prohibited
COMMIT
# Completed on Wed Feb 28 12:19:33 2018
~                                                                                                  
~                                                                                                       
"/etc/sysconfig/iptables" 17L, 654C

• （10）运行本地python连接MySQL代码，结果如下：

datebase version : 5.7.20-enterprise-commercial-advanced