Server emulator

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Server emulator is a term that refer to an internet server that mimics the behavior of another—usually more well-known—server. This is implemented through cloning or reverse engineering of the original server. Other synonyms include server reimplemention, server engine recreation, or server-side emulation.

The term is widely used to describe reimplementations of MMOG game servers, typically unauthorized clones of proprietary commercial software by a third party. Technically, a server emulator does not emulate by the traditional definition, which would permit software from one hardware platform to run on a different one; it is more similar to a terminal emulator.

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[edit] History

With the rising popularity of commercial MMORPG games, came the desire from ardent players of these games to run their own servers beside the ones run by the game's creator. Since the original server software is not usually available, the behavior of the server has to be re-engineered. This can be done by analyzing the data stream with the original server, or by disassembling and analyzing the client which is available.

Ultima Online was one of the first large MMORPGs. Due to its openness in implementation, server emulators arose very quickly, even during the beta stage of development. The destination to which the client connects was changeable by simply editing a text file. In beta stage the client-server data stream was not encrypted yet. The term server emulator became known through Ultima Online server reimplementation such as UOX, which was the pioneer. Many forks and reimplementations followed UOX, because its source code was released under the GNU General Public License relatively early. RunUO is today the most widely used UO-server emulator.

Game companies usually try to hinder emulator development by encrypting the data stream. However, since the client needs to understand the data, the "attacker" is always equipped with a deciphering machine. Therefore, the original game designer can only add layers of strenuousness to decipher and understand the data stream, he cannot hinder it with cryptographic tools.

[edit] Legality

Please note disclaimer: Wikipedia does not give legal advice.

The legality or illegality of server emulators is a recurrent argument. There are several branches that are of concern:

Copyright and Reverse engineering: The first issue is a possible infringement of the game creators copyright. As the case of Lotus v. Borland demonstrates, recreating "methods of operation" is not a copyright infingement. Thus, emulating copyrighted material is not a breach. However, this demands that the complete emulator is a work of its own. Sometimes the original server software leaks out of the company that created the game, for example AEGIS (Ragnarok Online). Use or distribution of this is definitely a copyright infringement. Modified versions of such original server software are not considered to be server emulators. The protocol that is used for communiciation between server and client is not subject to copyright, in contrast it could theoretically be patented, whereas software patents is a disputed field also. There are cases where a game creator effectively shut down popular private game servers by threatening lawsuits due to obvious copyright violations such as offering the client for download, or offering downloads of modified files from the original game package.

End User License Agreement and the Digital Millennium Copyright Act: Another legal issue is the EULA. Today most commercial MMORPGs require the user to sign a clause not to create or use server emulators when installing the client he bought. As shown in the case of Bnetd Vivendi Universal v. Jung, the DMCA can be relied on as well if the lawsuit is in the United States—The DMCA is a US specific law. They argued that server emulation requires the circumvention of copy protection. The server emulator company lost the suit and the bnetd.org domain was transferred to Blizzard.

[edit] Other common uses

  • Stolen original server software like AEGIS is not a server emulator.
  • Reimplementations of standardized protocols or server behavior is not considered to be emulation.
  • VMWare has a server edition, that is, although very seldom, sometimes mistakenly called "server emulator".

[edit] List of popular MMOG server emulators

[edit] See also

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