Short Answer
- Yes.
Long Answer
- Version 1.2 and 1.0 have almost the same "protocol", meaning their network communication is very similar. The only difference i saw was in the download mechanism. Not long ago i did create a fake 1.0 server that showed in 1.0 master-server list, but it was just a gateway to a 1.2 server (it can go both ways). This however doesn't work if you have a mod in 1.2 server that needs to be downloaded in 1.0 as the "fast-download" can't be achieved in 1.0.
- "Proxying" a real server and allowing players to join to it has its advantages and disadvantages.
Positive things:
- Regardless of the real server you can make the fake one show/hide in master-server.
- "Multi-Version" for 1.0 and 1.2. Fake server can accept both 1.0 and 1.2 players as long as you change the protocol of the connect packet.
- Complete control of the client. You cant actually know what the client is sending to the server as it is encoded (or maybe you know how) but you can disconnect him at any time, with any message.
- You can catch rcon commands. I haven't tested this yet, but as far as i remember rcon packet is sent in human-readable form. ( "\xff\xff\xff\xffrcon RCON_PASSWORD status")
- All players connected to the fake server have same IP. You can use this as, lets say a VPN to protect yourself.
- If your fake server is on the same machine as your original server, players with cracked keys will be able to join as it will appear they are connecting from LAN.
Negative things:
- Delay. When connected to the fake server i experienced a ping increase from 40-50 ms (regular) to 70-80 ms.
- All players connected to the fake server have same IP. Banning one fake player will result in banning them all.
- IF your fake server is on the same machine as your original server, players will have 0 GUID.
EDIT: Tested for rcon. Works.