CS:GO Dust 2 smokes

You can use http://www.canyouseeme.org/ . Just enter the port, 27015, and the website will try to connect to your server to see if the port is open or blocked by your ISP, forwarded (if you are behind a router) and accepting connections.

What you need are Server queries to recieve information from a running server. To work with queries you should have some develop-understanding because most of the query example around the net are written in php.

There's a documentation about it on the Valve Developer page.

After that you should start to read about the RCON Protocol.

Here're some things you can (de-)activate in the server.cfg.

Update:

I've found a open source library for php which make the things a bit easier.