emule

eMule is a free software peer-to-peer file sharing application that works with both the eDonkey network and the Kad network. eMule's codebase forms the basis for a Linux-specific client, xMule, and a multiplatform client, aMule.

The distinguishing features of eMule are the direct exchange of sources between client nodes, fast recovery of corrupted downloads, and the use of a credit system to reward frequent uploaders. Furthermore, eMule transmits data in Zlib-compressed form to save bandwidth. Another feature of eMule, or any eDonkey network client in general, is the ability to accept 'ed2k: URL scheme' (ed2k Links, eDonkey links) from a web browser and begin downloading the file(s) to which these links refer. These links ensure that the file being downloaded shares the same hash, and therefore is not a "fake". The matching of file sources is verified through the use of the MD4 algorithm.

eMule is coded in Visual C++ .NET using the Microsoft Foundation Classes and because it is a popular open-source program, hundreds of eMule mods (modifications of the original eMule) have appeared on the Internet.

History

The eMule project was started on May 13, 2002 by Hendrik Breitkreuz (also known as Merkur) who was dissatisfied with the original eDonkey2000 client. Over time more developers joined the effort. The source was first released at version 0.02 and published on SourceForge on July 6, 2002. eMule was first released as a binary on August 4, 2002 at version 0.05a. The 'Credit System' was implemented for the first time on September 14, 2002 in version 0.19a. The eMule project website started up on December 8, 2003. Since its inception, eMule has been downloaded over 218 million times (as of August 2006).

Recent events

Current versions (v0.40+) of eMule have added support for the Kad Network. This network has an implementation of the Kademlia protocol, which does not rely on central servers as the eDonkey network does, but is an implementation of a Distributed hash table.

Also added in recent versions were "Unicode Search" (allowing for searches for files in non-Latin alphabets) and the ability (not supported in Kad Network) to search servers for files with complete sources of unfinished files.

In new versions, a "Bad source list" was added. The application adds an IP address to this list after one unsuccessful connection. After adding an IP to the "Bad source list", the application treats this IP as a "dead" IP. Unavailable IPs are banned for a time period from 15 to 45 minutes. Some users have complained that it leads to a loss of active sources and subsequently slows download speed.

Other recent additions include: the ability to run eMule from a user account with limited privileges (thus enhancing security), and intelligent corruption handling (so that a corrupted chunk, 9.28 MB in size, does not need to be re-downloaded entirely).

The 0.46b version added the creation and management of "eMule collection" files, which contain a set of links to files intended to be downloaded as a set.

The 0.47b version adds protocol obfuscation to bypass ISP bandwidth throttling. It may be good for users not willing to change their Internet service provider, but it may lead to even stricter bandwidth limiting from the ISPs. (Note: this protocol obfuscation cannot be used to ensure privacy or anonymity.)

eMule is now considered a stable product, and new versions are not released as often as they used to be; five to six months is now a typical time interval between releases. The latest version (as of September 14, 2006) is 0.47c, released in September, 2006.

It is recommended to change the default ports of eMule to higher numbers (for example, 20000 instead of 4662), because recently many ISPs are bandwidth throttling default P2P ports resulting in slow performances. Starting from version 0.47b, eMule will automatically select two ports at random in the startup wizard.

Official Sites vs Fake Sites

The official website is located at http://www.emule-project.net. At this site, the latest version of eMule can always be downloaded for free. You may also download past versions of eMule at http://sourceforge.net/projects/emule

Fake sites

Other similar domain names which ask for payment in order to login or download a purportedly newer version of emule are scam sites.

eMule mods

As a popular open source program, eMule has many variants, usually called mods. Some mods started as a fork of an eMule code, and then continued to develop independently from the official version. A popular mod of this type is eMule Plus, although it does not have Kademlia protocol implemented. Other mods follow official eMule releases, and make their own releases based on each new release of the official version. Often features first debuted in a mod later find their way into the official version.

Mod links

Some eMule mods:

• eMulePlus
• eMule Xtreme
• eMule Morph
• Neomule
• eMule ScarAngel
• eMule StulleMule
• eMule TK4

List of eMule mods: eMule-MoDs.de (partly German)

Network status

(data for eDonkey network)

• Number of concurrent users : 3 - 5 million (correct number is unknown since many new servers are faking their number of users. latest users statistics can be found at : Slyck.com).
• Number of concurrent shared files: ~600 million.

See also

• eDonkey network
• aMule Linux / Mac OS X client
• Shareaza multi-network client
• MLDonkey multi-network client
• File sharing
• File-sharing program
• Comparison of file sharing applications
• Comparison of eDonkey software

External links

• eMule project Official site
• eMule on SourceForge (SourceForge) Contains archives of past versions of eMule
• KademliaSkins.Net Skins for eMule
• eMule content database A collection of files released on the ED2K network
• eMule Protocol Specification (PDF) eMule Protocol specification by Danny Bickson and Yoram Kulbak from HUJI.