Also if someone likes halo online, they can always play Halo 1 Custom Edition. It has also maps from halo 2 made by users.
It only gets 20 people at max in peak hours, I have a gaming pc and I've never ever played this game on it
I don't have a gaming PC, so online for Halo 2 was shut down long ago in my world, but that is a true shame that they're shutting down the servers.
Hope is not lost, there will be people who will make servers and it will continue for the people who want to play.