By now Microsoft will have discontinued the Xbox Live support for the original console. This means servers for all games will have been shut down.
This now means Xbox games can no longer be played online in any way, not even playing backward compatible titles on Xbox 360.
The Halo 2 community is in particular hit by this as it has mainatined a decent number of users since its release in 2004.
“To reach our aspiration, we need to make changes to the service that are incompatible with our original Xbox v1 games,” was what Microsoft’s Marc Whitten said when the decision to shut down support was announced.