Setup a proxy for MySQL server on Ubuntu located in intranet

I have a MySQL server instance running in office's intranet, which only can not be accessed from internet. Meanwhile, I have a proxy server as a gateway connected to both networks, and I therefore I could setup an MySQL proxy!

Fortunately, after searing on web, a program called mysql-proxy could solve my problem! Also, it is included in Ubuntu's APT source.

Installation as the following steps:

# install the program
$ sudo apt-get install mysql-proxy

# write a proxy config file
$ vim config.conf

# the content is my situation
daemon = 1
pid-file = /var/run/
log-file = /var/log/mysql-proxy.log
log-level = debug
max-open-files = 4096
plugins = admin,proxy
user = root

proxy-address = proxy-server-IP:4567

proxy-backend-addresses = mysql-server-IP:3306
admin-username = admin
admin-password = admin
admin-lua-script = /usr/lib/mysql-proxy/lua/admin.lua

# run the proxy
$ sudo mysql-proxy --defaults-file=config.conf

Then you may have a proxy running, listening port 4567. If it doesn't work, check the logfile in /var/log/mysql-proxy.log.

When proxy server is ready, create an user which is accessible to MySQL server from proxy server.

# on MySQL server, execute following command to add a user:
mysql> grant all on dbname.* to username@proxy-server-IP identified by 'pw';

Finally, you can have access MySQL server from internet by a proxy!