For all who wants to play the online multiplayer there are several ways to do that.

#1 - Host File (Systemwide)
On Windows go to "C:\Windows\System32\drivers\etc" and open the "hosts" file with your Editor than add this line to it:

192.246.40.56 master.quake3arena.com

#2 - autoexec.cfg for ioquake3 and other source ports
On Windows go to "%AppData%\Quake3\baseq3" and make a new "autoexec.cfg" then past these master servers addresses to it:

//Quake 3 Arena Master Servers
//www.quakeservers.net
set sv_master1 "master0.excessiveplus.net:27950"
set sv_master2 "master.ioquake3.org:27950"
set sv_master3 "master.maverickservers.com:27950"
set sv_master4 "dpmaster.deathmask.net:27950"
set sv_master5 "dctalk.no-ip.info:27950"
set sv_master6 "master3.idsoftware.com:27950"