1、程序报错： com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link 2、尝试远程连接数据库： [root@inode1 ~]# mysql -h192.168.1.165 -uroot -p123456 ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.1.165' (113)
3、问题找到了，不能连接远程数据库。
4、测试是否能ping到远程机器
[root@inode1 ~]# ping 192.168.1.165 PING 192.168.1.165 (192.168.1.165) 56(84) bytes of data. 64 bytes from 192.168.1.165: icmp_seq=1 ttl=128 time=0.776 ms 64 bytes from 192.168.1.165: icmp_seq=2 ttl=128 time=1.26 ms 64 bytes from 192.168.1.165: icmp_seq=3 ttl=128 time=1.19 ms ^C --- 192.168.1.165 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2008ms rtt min/avg/max/mdev = 0.776/1.078/1.268/0.215 ms
说明网络是连通的，再测试以下端口号
5、登录到数据库端
[root@dbServer ~]# mysql -uroot -p123456 Welcome to the MariaDB monitor. Commands end with ; or g. Your MariaDB connection id is 11 Server version: 5.5.52-MariaDB MariaDB Server Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. MariaDB [(none)]> select user,host,password from mysql.user; ------ ----------- ------------------------------------------- | user | host | password | ------ ----------- ------------------------------------------- | root | localhost | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | | root | 127.0.0.1 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | | root | ::1 | *6BB4837EB74329105EE4568DDA7DC67ED2CA2AD9 | ------ ----------- -------------------------------------------
添加%
MariaDB [(none)]> grant all privileges on *.* to 'root'@'%' identified by '123456'; Query OK, 0 rows affected (0.00 sec) MariaDB [(none)]> flush privileges; Query OK, 0 rows affected (0.00 sec)
再次远程访问：
[root@hadron ~]# mysql -h192.168.1.165 -uroot -p123456 ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.1.165' (113)
6、还是无法连接到数据库，可能不能访问端口号，再次测试
[root@hadron ~]# telnet 192.168.1.165 3306 Trying 192.168.1.165... telnet: connect to address 192.168.1.165: No route to host
找到问题所在了，防火墙屏蔽了这个端口号。
7、直接关闭防火墙即可。
[root@dbServer ~]# systemctl disable firewalld Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service. Removed symlink /etc/systemd/system/basic.target.wants/firewalld.service. [root@dbServer ~]# service firewalld stop Redirecting to /bin/systemctl stop firewalld.service
再次远程访问
[root@hadron ~]# telnet 192.168.1.165 3306 Trying 192.168.1.165... telnet: connect to address 192.168.1.165: No route to host [root@hadron ~]# mysql -h192.168.1.165 -uroot -p123456 Welcome to the MariaDB monitor. Commands end with ; or g. Your MariaDB connection id is 7 Server version: 5.5.52-MariaDB MariaDB Server Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others. Type 'help;' or 'h' for help. Type 'c' to clear the current input statement. MariaDB [(none)]>
成功了。
【2018年01月30日再次遇到这个问题】
在ubuntu下安装MariaDB 10，遇到远程无法登录
root@kylin3:/etc/mysql/mariadb.conf.d# mysql -uroot -p123456 -h 192.168.1.161 ERROR 2003 (HY000): Can't connect to MySQL server on '192.168.1.161' (111 "Connection refused")
按照之前的方法操作一遍，还是没有解决问题。
这个问题又百度了一个下午，掉坑了。
静心再看看，喜出望外：
查看端口号，发现3306对应的地址依然时127.0.0.1，修改没有起作用
root@kylin1:/etc/mysql# netstat -npl|grep 3306 tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 9191/mysqld
可能进程出问题了，直接kill掉，再启动
root@kylin1:/etc/mysql# kill -9 9191 root@kylin1:/etc/mysql# netstat -npl|grep 3306 root@kylin1:/etc/mysql# systemctl restart mysql 再次查看端口号，正常了 root@kylin1:/etc/mysql# netstat -npl|grep 3306 tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 23476/mysqld root@kylin1:/etc/mysql#
也可以远程登录了。
ERROR 2003 (HY000): Can't connect to MySQL server问题
解决办法总结：
1、确定远程机器的防火墙关闭，或在防火墙允许3306端口号
2、确定数据库允许远程访问，通过语句grant all privileges on *.* to 'root'@'%' identified by '123456'即可。
3、如果上面方法还是没有解决。直接kill进程，重启。
