Gatekeeper may get in the way of running HaloMD since we don't pay Apple's fee.
To bypass it, simply hold control and click on HaloMD, and choose 'Open'.
To host games: "Start" Halo, and create an Internet game under Multiplayer.
Depending on your network, your server may not show up to your peers. To resolve this, you can first try installing Port Mapper from the Extensions menu. If that does not work, then you need to open ports 2302 - 2303 on UDP.
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