blocking MapleStory port 8484

My son (13) is playing MapleStory to the extreme. I have found out that by blocking port 8484 I can block the game. I found a program that can block it but it puts a icon in the systray and there is no way I can find to make it invisible. I can block the the game using Sygate firewall but I am trying to find a easy way to block it invisibly on the desktop so he won't be able to easily disable it. I have a router (Verizon FIOS) and I see how to block IP's but I don't see how to block ports with it. Is there a way to block ports on a PC?

 

right click on your adapter > properties > tcp/ip > properties > advanced > options tab > tcp/ip Filtering > parenting class

 

Thanks, I found the tcp/ip Filtering but I didn't see parenting class anywhere and it seems I would have to list all the ports I want but exclude 8484 or whatever. It seems it should be easier. I am running WinXP pro. I searched a little on the web about parenting class and the install tcp/ip services on the computer but I still couldn't find anything on parenting class.

 

Are you sure your router won't let you block specific ports? I believe most routers can do that. A reference: http://www.ibiblio.org/security/articles/ports.html

Is that router actually a Verizon brand? What about blocking an IP rather than a specific port, assuming they have a static IP.

 

You can also password protect your firewall settings! And you can hide it from the system tray!

 

Thanks for the suggestions, I recently had to replace the router because it kept losing it's internet connection and I asked to technician about it. I did a little hunting around and found some things to stop outside connections. It still doesn't have a way of blocking a port. The sygate firewall can block the app and also put it on a schedule if one wishes and it can password protect the settings and hide the icon is systray.
Thanks for the ideas