It seems as of 2018 there are people still using their first original Xbox to play Halo 2 online via x-linked so no need to rewind time you can always play the classic Halo 2 game on your Xbox via this tutorial enjoy! Also Halo 2 is the most played game on X linked kai. From what I see you connect your Xbox to your network via Ethernet behind the Xbox you download install X linked to your computer you then sign in and start playing it's that simple
How to:
https://youtu.be/JFhpVzPd3Nc
Xlinked Kai halo 2 xbox gameplay:
https://youtu.be/EC3T_X3zy7I
Xlinked Kai halo 2 xbox 360 gameplay:
https://youtu.be/8SmJA2mJ1hE