These are some servers I installed. They are low-traffic :)
This server allows to play the Chocolate Doom video game (a FPS).
http://www.chocolate-doom.org/
http://master.chocolate-doom.org/
Address: yugiohjcj.cf
Port: 2342 (UDP)
This server allows to play the Counter-strike video game (a FPS).
Address: yugiohjcj.cf
Port: 27015 (UDP)
This server allows to play the Frozen Bubble video game (a puzzle game).
Address: yugiohjcj.cf
Port: 1511 (TCP)
This server allows to play the Galaxy Forces video game.
Address: yugiohjcj.cf
Port: 1999 (TCP)
This server allows to play the Hedgewars video game.
Address: yugiohjcj.cf
Port: 46631 (TCP)
This server allows to play the Quake 3 Arena video game (a FPS).
Address: yugiohjcj.cf
Port: 27960 (UDP)
This server allows to chat.
Address: yugiohjcj.cf
Port: 6697 (TCP)
This server allows to play the Minetest video game.
https://forum.minetest.net/viewtopic.php?f=10&t=14795
Address: yugiohjcj.cf
Port: 30000 (UDP)
This server allows to voice chat while playing network video games. Thanks to the VoIP. It replaces the well known TeamSpeak.
http://mumble.sourceforge.net/
Address: yugiohjcj.cf
Port: 64738 (TCP/UDP)
This server allows to access to an IRC server through a web interface.
http://webirc-minetest.yugiohjcj.cf/
Address: yugiohjcj.cf
Port: 9090 (TCP)
This server allows to play the NetRPG video game. The client can be downloaded in the "My software" section.
Address: yugiohjcj.cf
Port: 9999 (TCP)
This server allows to play the Teeworlds video game.
Address: yugiohjcj.cf
Port: 8303 (UDP)
This server hosts web sites. At this time, the GenSiteweb web site is hosted. It allows the easy creation of web sites.
Address: yugiohjcj.cf
Port: 80 (TCP), 443 (TCP)