In 2011, LEGO Universe, a massively-multiplayer online role play game by the LEGO Group has been shutdown, making it impossible to play the game anymore. The original servers went offline, and the clients could not work anymore.
Since before the closing, fans have worked on creating custom servers to replace the official ones, and this effort has been continued to this day.
Originally, humanoid24 created a first test server, which was improved upon as the LUNI Server by a community lead by raffa505. That project, with contributions by jon002, CuzItsJonny and myself (Xiphoseer) can be found in its latest iteration at https://github.com/LUNIServer/UniverseServer.
Another implementation based on humanoids original test version is DLU by DarwinAnim8or which is currently developed in private by him and a team of developers including TheMachine, Jon002, Matt/Extra and myself.
humanoid is still working on an implementation of the server, joined by lcdr. They have released a detailed documentation of their findings at https://docs.google.com/document/d/1v9GB1gNwO0C81Rhd4imbaLN7z-R0zpK5sYJMbxPP3Kc. Most of this work has only been possible because pwjones has captured and released network traffic from the original game.
To read more about the backstory of LU server development, consider reading A bit of backstory, if you haven’t already done so.
If you want to set up a server, you will need to compile a public project yourself or write your own server with the help of the documentation, since most public binarys are either incomplete, corrupted or out of date. Keep in mind that hosting unfinished software on your machine will likely make it vulnerable to malicious activities and all public versions use the official RakNet implementation which is requires a Windows operating system.
Even before multiplayer was introduced, people wanted to have public servers to play with their friends. This was first possible when I published my source that contained multiplayer functionality, leading to CDFalcon setting up the first public server. At this point, CuzItsJonny provides the only sane public server at http://jonnyvps.de/. Other servers may exist, but I strongly discourage using them, as server owners without knowledge on how to fix bugs and maintain the server should not be encouraged.
The game initially had two modes to download the game data. Full Download would take multiple hours, but you would have all game files required on your PC. The ‘As required’ mode downloaded the files just before you needed them, making it possible to start the game with barely any download time. Most people have chosen the second option for obvious reasons, this is the reason why clients that still work are so rare.
There is also a client branded Nexus2, which has been artificially reassembled, which works fine in most cases (I still use it), but may not be your best choice.
If you have an old client of around 10GB in size, ideally with a different version or language than the Blast Client lying around, feel free to send me a message on Skype (Xiphoseer), to see if it contains data that is not yet known.
Yes, the LUNI Server mentioned here is the project that Timtech advertised. He has been given donations to make a public server and failed to do so, never contributed anything relevant to the source, and made the original developers abandon LUNI. It’s not his project, he just ended up killing it.
UPDATE 06.01.2016: CuzItsJonnys server is no longer available, due to malicious activity against him. He might reopen a private whitelisted server at some point.