"HeadToHead" mission rewritten in Mar2026 commencing in LAC V9.91.

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For many years, LAC's "HeadToHead" mission has been the abandoned stepchild among our multi-player online missions. It hasn't received any attention from our developers for about 8 years. But since March of 2026, Alpha Testers have been exercising LAC Version 9.91 with a rewritten "HeadToHead" mission that is much more interesting than the old one.

This "HeadToHead" mission is the only LAC mission that can be configured in BOTH of our supported network modes. Those two modes are:

1 of 2: "Client/Server" mode. This is LAC's default. Under this mode, every LAC player is a "client" of the free, open-source LAC Server. In this mode, as many as 10 individual players can all connect to the same mission in the same Realm and fly together.

2 of 2: "PeerToPeer" mode. Most LAC players have never tried this mode. In order to activate it, players must edit their LacConfig.txt file and they must reset the least significant bit of the "NetworkMode" attribute. (This means that "NetworkMode" will always contain an even number. This usually means "subtract 1" from the odd number that is usually contained there). In "PeerToPeer" mode, any individual copy of LAC must be specifically configured to communicate with just one other LAC player . That LAC player replaces references to the LAC Server in the configuration file. Accordingly, four additional items in the LacConfig.txt file must contain the IP address of that other LAC player. As an example, to configure your copy of LAC to communicate with another LAC player whose Internet Address is 171.76.220.6, you would edit four variables in "LacConfig.txt" as follows:

ServerIpByte1of4 = 171
ServerIpByte2of4 = 76
ServerIpByte3of4 = 220
ServerIpByte4of4 = 6

In this mode, as many as TWO players can enjoy the "HeadToHead" mission. Other missions DEMAND "Client/Server" mode, but the "HeadToHead" mission works in BOTH modes (as many as 10 players when connecting through the Server in Client/Server mode, but limited to 2 players in "PeerToPeer" mode).

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In most cases when you want to use PeerToPeer mode, it will also be necessary for you to enable "Port Forwarding" in your NAT router, forwarding all incoming Internet traffic using UDP port 51100 to the IP address of your LAC host. This "Port Forwarding" setup will be a lot easier to configure and manage if you also give your LAC host a "static IP" address.

The terms "Port Forwarding" and "Static IP address" and "UDP" are well-known terms and you can find abundant information published about them through a conventional Web search or through a query to "chatgpt.com", to "grok.com", to "gemini.google.com", or to "perplexity.ai".

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Of course, it isn't enough for just ONE of the two players to edit his LacConfig.txt file and specify the IP address of his peer; BOTH players must do that! Each player references the other by his IP or Internet address. And both players must ensure that their copy of LAC is operating in "Peer-to-Peer" network mode by ensuring that the "NetworkMode" variable has an EVEN number (not an odd number) value. When two LAC players have both configured their computers in this manner by editing each of the two LacConfig.txt files, it's as if each were operating as a "LAC Server" to the other.

Note that neither of these two cooperating "Peer-to-Peer" machines is running any extra code. They aren't really running any "server" processes. It's just that LAC's lightweight client network code is written to be adaptable to this kind of operation. Accordingly, there is no need to worry that one of the two computers may not be powerful enough to act as "the server". There's absolutely no difference in workload between the two Peer-to-Peer hosts, and neither is working any harder than would be necessary if they were communicating with one other player through LAC's regular server.