Counter Strike Source : Orange Box and Call Of Duty Modern Warfare Port Blockade

Hello,

I have been using NIS since 2011 till today.Recently I have been facing a weird problem which is when ever I try to do some online gaming each and every game can flawlessly connect and I can play for the day,but the following day I somehow can't connect anymore.In the both above mentioned games the same problem has occured resulting to a error message generating "Server Connection : Timed Out". I might also mention that also in another game the same issues have occured and as a result I can't play them anymore.I tried to contact my local ISP and they gave me a good go from their side about no port restrictions.It has came to my knowledge that NIS has some issues regarding online gaming of those particular games.I tried to un-install the NIS and do a default restore of the Windows FireWall but it did not solve the problem.At the moment I am using NIS 2012 and the problem still is there.

I might mention that the required ports running are :

 

28960,27015-17,27021

 

Is this a port blockade issue from NIS or a HomeGroup Issues?

Please help me out!

 

Thanks In Advance