Troubleshooting

Swivel and Reliant are blocked on KSP 1.12.2+

If you are using LMP 0.28 on KSP 1.12.2+ with ModControl enabled (default), the Swivel and Reliant engines might be banned. They are called liquidEngine.v2 and liquidEngine2.v2 internally and LVT-45 / LV-T30 in short in the UI.

This is due to a rework of the engines in KSP 1.12.2.

You can fix this by upgrading to 0.29, or adjusting LMPModControl.xml (more information) to allow-list the reworked variants in AllowedParts:

<AllowedParts>
    <string>liquidEngine2.v2</string>
    <string>liquidEngine.v2</string>
</AllowedParts>

Can't connect to my friend server / A friend cannot connect to my server

• If you use Hamachi, proxies, VPNs or something similar, disable them. Hamachi is confirmed to break LMP.
• Read the Create a server page including the Important notes section
• Check that automatic port forwarding worked. The server will print UPnP active. Port: 8800 Udp opened! if it was successful.
  If you don't see this line, open the port in your router interface.
• If server list connection does not work try direct connection
• Try to connect to a public server to see if it's a problem of the host or the client
• Try enabling IPv6 on the server (see Create a server # Network, it can help with (symmetric) NAT issues
• Make sure the firewall on the server is configured to allow incoming traffic for LMP, especially if the client is in the same local network as the server.
  • Windows: Set the network profile to private
• Read the page on NAT punchthrough to get an understanding of LMP's connection setup process and where it might fail.
  Am I behind symmetric NAT? How to find out:
  • https://tomchen.github.io/symmetric-nat-test/
  • Open the website of multiple master servers, look for your server and compare the port in the leftmost column. If it differs between master servers, you are behind symmetric NAT and NAT punchthrough won't work. You must confirm that port forwarding worked (UPnP or manual)

I can see me friend but they can't see me / I can't see other players

• Make sure you are out of the safety bubble around the space center.
• This usually happens when you use a part that the other players don't have. You are probably using a part from a DLC or a mod that your friend doesn't have.

There are lags

• If your KSP clock is yellow it means that your KSP is struggling to keep the physics clock at 30fps. This usually happens when the vessel has too many parts and as LMP doesn't have server side physics the KSP clock will have to sync with the server clock once the difference is big. During that synchronization the throttle is reset and the vessel "jumps". Try to use vessels with less parts or reduce the amount of visual mods so the KSP clock is not yellow

I am getting an error message

1. Lidgren: ERRORMESSAGE -- Failed to send packet: System.Net.Sockets.SocketException (10051): A socket operation was attempted to an unreachable network.
   This means your ListenAddress in ConnectionSettings.xml is invalid. It needs to be either [::] or 0.0.0.0, with the first one allowing IPv6 connections, which can help in some difficult NAT/firewall situations.

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Versioning:

• LMP will only be compatible with the latest KSP version. We don't support older KSP versions as this is very time consuming and we have limited resources. If you want LMP to work in an older KSP version, feel free to download the code and compile it for your needs

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Limitations:

• LMP experience is a bit different from the standard KSP experience. Be sure to check the limitations page to see what behaviours are different

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Linux:

• Use environment variable LC_ALL=C in server and in client to avoid localization issues.
  More info here.

General:

• There might be issues when playing with mods. Check mod support
• Be sure to use the latest version of KSP. We do not support old KSP versions

Server:

• Console window closes instantly, server doesn't start: You have to install .NET 5. Details
• Read the important notes section in the create a server page

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Slow connections

If you have a slow connection you might need to increase the timeout values.

On the server:

In the ConnectionSettings.xml edit the node:

<!--Connection timeout in ms. If no heartbeats are received after this interval, the client is disconnected.-->
<ConnectionMsTimeout>30000</ConnectionMsTimeout>

And increase it to 60000 (60 seconds) for example

You can try to decrease the MTU size value if screenshots take too much time to be sent to clients.

On the client:

• Open KSP.
• In the KSP menu, Go to the LMP settings.
• In the Network configuration menu, increase the timeout value or set it to infinite.
• Consider lowering the MTU value if the screenshots take too much time to be uploaded.