Tachyons Can't Connect to Server? Version, UDP and Login Fixes

When a player cannot connect to a Tachyons server, it is almost always one of four things: their client is a different release from the server (the server logs Client version [...] - Server version [...]), the server's UDP port is blocked so the connection times out during UDP registration, they typed a different password for a name that already exists (Wrong login or password.), or they are using the itch.io build against a CE server. Match the CE release, open the port for both TCP and UDP, and log in with the same name and password every time.

Tachyons is a small community game, so there is no big troubleshooting wiki to lean on. This guide works from the messages the CE server and client actually print.

Check 1: the same release on both sides

The Tachyons CE server and client carry a version string (for v1.0.2 it is CE.1.0.2) and the server compares them on every login. A mismatch is refused, and the server console logs the client's version next to its own.

The fix is to have everyone download TachyonsCE.zip from the same release on the Tachyons CE releases page and play with the client in its client folder. Do not mix and match files from different releases.

Check 2: "timed out during UDP registration"

Tachyons uses the KryoNet networking library. A client first connects over TCP, then registers a UDP channel on the same port. If TCP gets through and UDP does not, the client sees a connection start and then fails with a message like:

Connected, but timed out during UDP registration

That means the server's port is open for TCP only. Fix it on the server side:

1. Forward the port (30303 by default, or whatever SERVER_PORT says in config.cfg) for both TCP and UDP on the router.
2. Allow both in the firewall:

sudo ufw allow 30303/tcp
sudo ufw allow 30303/udp

netsh advfirewall firewall add rule name="Tachyons TCP" dir=in action=allow protocol=TCP localport=30303
netsh advfirewall firewall add rule name="Tachyons UDP" dir=in action=allow protocol=UDP localport=30303

The router side is covered in how to port forward a game server.

If the error says it timed out during TCP registration instead, nothing is getting through at all: wrong address, wrong port, server not running, or the port closed for TCP too.

Check 3: the right port

The client asks for an address and a port separately. Old guides and forum posts say 30303, which is only the default. If the server's config.cfg has another SERVER_PORT, that is the one players must enter. On a hosted server, use the port shown with your server address.

To confirm the server is listening where you think, look for this line in its console at startup:

[Server] Network server started on port: 30303

Check 4: "Wrong login or password."

Tachyons servers have their own accounts. The first time a name logs in, the server creates the account with that password (Registered new player in the console). From then on, that name only works with that password.

• A player who mistyped their password the first time must use the mistyped one, or pick a new name.
• Two friends who chose the same name: the second gets refused. One of them needs a different name.
• Login or password is empty! means a field was left blank.

There is no in game password reset. If a player is locked out of their character, the admin can stop the server, back up DataBase, and remove that player's files from DataBase/Players so the name can be registered again. That loses the character, so make sure it is what they want.

Check 5: "You are banned."

The player, or their IP, is in DataBase/BanList.dat. In the server console:

/unban PlayerName
/unbanip 203.0.113.45

Check 6: the server is not really up

If the console never prints [Server] SERVER STARTED., nobody can join. The usual causes:

Always stop the server with /exit so it saves cleanly.

Check 7: Java on Linux and Mac clients

Windows players run TachyonsCE_Client.exe, which brings its own Java. Linux and macOS players run TachyonsCE.jar and need Java installed. A client that does not open at all is a Java problem, not a server problem.

On a GamezServers server

A GamezServers Tachyons server sets the port for you on both protocols, so the UDP registration problem does not come from a missing router rule, and players use the address and port shown in the panel. The Version setting picks which CE release the server runs, so you can match it to the client your crew downloaded. The live console shows logins, version mismatches and /unban, and DataBase is in the file manager with one click backups. More on the server itself in how to host a Tachyons server.

FAQ

Why can't I join a Tachyons server with the itch.io version?

The server checks the client's version on login. A CE server only accepts the CE client from the same release.

What does "timed out during UDP registration" mean in Tachyons?

The TCP connection worked but UDP is blocked. Open the server port for UDP as well as TCP.

How do I reset my Tachyons password?

There is no reset command. Use the original password, pick a new name, or ask the admin to remove your player files so the name can be registered again.

What port does Tachyons use?

30303 by default, set with SERVER_PORT in config.cfg, on both TCP and UDP.