What is multicast filtering?

[SNIL]

The reason I asked is because I had to disable it in my router to finally get rid of all the lag in World of Warcraft. What does it do and should I have it enabled? I have the SPI firewall still up and my MTU set manually to 1500 on my cable setup.

 

[REB_ElMagnifico]

I am not sure what disable multicast filtering would do on that particular router, however...
Multicasting is a form of broadcasting which, in a home network, basically means that useless information was being sent across your network. Disabling that option probably acted like a weed killer in a garden...now the flowers can breath.

 

[REB_ElMagnifico]

Well...after pondering a bit after answering your question, I began to question myself, so I did some research...
From this website: http://support.3com.com/infodeli/tools/switches/ss3/management/ug/mlticast.htm
I interpret that multicast filtering does the opposite of what I said. So disabling the filter should actually decrease performance (according to the article). But if disabling the option solved the problem, then...awesome.