- Direct Connect (file sharing)
Direct connect is a peer-to-peer file sharing protocol. Direct connect clients connect to a central hub and can download files directly from one another. Advanced Direct Connect can be considered a successor protocol.
- 1 History
- 2 Protocol
- 3 Hub software
- 4 Client Software
- 5 Other Software
- 6 Hublists
- 7 Direct Connect used for DDoS attacks
- 8 References
- 9 External links
NeoModus was started as a company funded by the adware "Direct Connect" by Jonathan Hess in November, 1999 while he was in high school. The first third-party client was called "DClite", which never fully supported the file sharing aspects of the protocol. Hess released a new version of Direct Connect, requiring a simple encryption key to initiate a connection, locking out third-party clients. The key was cracked, and the author of DClite released a new version of DClite compatible with the new software from NeoModus. Some time after, DClite was rewritten as Open Direct Connect with goals of having an MDI user interface and using plug-ins for file sharing protocols (similar to MLDonkey). Open Direct Connect also did not have complete support for the full file sharing aspects of the protocol, but a port to Java did. Some time later, other clients such as DCTC (Direct Connect Text Client) and DC++ became popular.
The Direct connect protocol is a text-based computer protocol, in which commands and their information are sent in clear text, without encryption in original Neo-Modus software (of course encryption is available as protocol extension). As clients connect to a central source of distribution (the hub) of information, the hub is required to have a substantial amount of upload bandwidth available.
There is no official specification of the protocol. This means that every client and hub besides the original Neo-modus client and hub has been forced to reverse engineer the information. As such, any protocol specification this article may reference is likely either inaccurate and/or incomplete.
The client-server (as well in client-client, where one acts as "server") aspect of the protocol stipulates that the server speak first when a connection has been made. For example, when a client connect to a hub's socket, the hub is first to talk to the client.
The protocol don't have specified default character encoding for clients or hubs. In original client and hub is use Ascii encoding of Operating system. This allow to move to UTF-8 encoding in newer software.
Port 411 is the default port for hubs, and 412 for client-to-client connections. If either of these ports is already in use, the next higher port is used. For example, if 411, 412 and 413 are in use, then port 414 will be used.
Hub addresses are in the following form: dchub://example.com[:411], where 411 is an optional port.
There is no global identification scheme; users are identified with their nickname on a hub-to-hub basis.
An incoming request for a client-client connection cannot be linked with an actual connection.
A search result cannot be linked with a particular search.
Supported by the protocol is the ability to kick or move (redirect) a user to another hub. There is no restriction on where a user might be redirected to. If a user is kicked, the hub isn't required to give the user a specific reason. However, if another client in power instructs the hub to kick, that client may send out a notification message before doing so. Redirecting a user must be accompanied by a reason. There is no HTTP referer equivalent.
Hubs may send out user commands to clients. These commands are only raw protocol commands, and are used mostly for making a particular task simpler. For example, the hub cannot send a user command that will trigger the default browser to visit a website. It can however add the command "+rules" (where '+' indicates to the hub that it's a command - this may vary) to display the hub's rules.
The peer-to-peer part of the protocol is based on a concept of "slots" (similar to number of open positions for a job). These slots denote the number of people that are allowed to download from a user at any one time. These slots are controlled by the client.
In client-to-client connections, the parties negotiate a random number to see who should be allowed to download first. The client with the highest number wins.
There are two kinds of modes a user can be in, either "active" or "passive" mode. Clients using active mode can download from anyone else on the network. Clients using passive mode users can only download from active users. In NeoModus Direct Connect, passive mode users receive other passive mode users' search results, while the user will not be able to download anything. In DC++, users will not receive those search results. In NeoModus Direct Connect, all users will be sent at most five search results per query. If a user has searched, DC++ will respond with ten search results when the user is in active mode, or five, when the user is in passive mode. Passive clients will be sent search results through the hub, while active clients will receive the results directly.
Protocol delimiters are '$', '|' and ' ' (space). Protocol have for them (and few others) escape sequence and most software use them correctly in login (Lock to Key) sequence. For some reason that escape sequence was ignored by DC++ developers and they use HTML equivalent if these characters are to be viewed by the user.
Continued interest exists in features such as ratings and language packs. However, the authors of DC++ have been actively working on a complete replacement of the Direct connect protocol called Advanced Direct Connect.
One example of an added feature to the protocol, in comparison with the original protocol, is the broadcasting of Tiger-Tree Hashing of shared files (TTH). The advantages of this include verifying that a file is downloaded correctly, and the ability to find files independently of their names.
Direct Connect hubs are central servers to which clients connect, thus the networks are not as decentralized as Gnutella or FastTrack. Hubs provide information about the clients, as well as file-searching and chat capabilities. File transfers are done directly between clients, in true peer-to-peer fashion.
Hubs often have special areas of interest. Many have requirements on the total size of the files that their members share (share size), and restrictions on the content and quality of shares. A hub can have any arbitrary rule. Hubs can allow users to register and provide user authentication. The authentication is also in clear text. The hub may choose certain individuals as operators (similar to IRC operators) to enforce said rules if the hub itself cannot.
While not directly supported by the protocol, hub linking software exists. The software allow multiple hubs to be connected, allowing users to share and / or chat with people on the other linked hubs. Direct connect hubs have difficulty scaling, due to the broadcast-centricity of the protocol.
NMDC hub FOSS Software license Active Latest version (release date) GUI CLI Other IPv6 support Programming language Based on UFOHub No Proprietary
Yes v7.9.11 (2011-09-15) Yes Unknown Unknown No Unknown UFOHub PTDCH Yes GNU GPL Yes Yes Unknown Unknown No Visual Basic, Jscript, VBscript DDCH Dtella Yes GNU GPL Yes 1.2.6 (2010-01-22) Unknown Unknown Unknown No Python HeXHub Yes Open Software License Yes 5.07 (2011-05-29) Yes Unknown Unknown No Assembly Open Direct Connect Hub Yes GNU GPL No 0.8.2 (2010-04-09) No Unknown Unknown No C, Perl Flexhub Yes GNU AGPL Yes Unknown Yes Unknown No Lua PtokaX Yes GNU GPL Yes 0.4.2.0 (11 September 2011) Yes Yes Unknown Yes C++, Lua RusHub Yes GNU GPL Yes 2.3.7 (23 October 2011) No Yes Unknown Yes C++, Lua VerliHub Yes GNU GPL Yes 0.9.8e-r2 (2009-07-20) No Yes Unknown No C++, Lua, Python Eximius No Proprietary
Yes Yes Unknown Unknown No C#, Lua DB Hub Yes GNU GPL No Unknown Unknown Unknown No Unknown OpenDCHub openDCd Yes GNU GPL No Unknown Unknown Unknown No Unknown DDCH DevDirect Connect Hub Unknown Unknown No Yes No No No Visual Basic, Jscript py-dchub Yes MIT License No 0.2.4 (2006-02-13) Unknown Unknown Unknown No Python Aquila Yes GNU GPL No No Yes No No C++, Lua YnHub No Proprietary
No 1.036 (2008-03-23) Yes No No No Delphi X-Hub Unknown Unknown No 0.3.1.0 () Unknown Unknown Unknown No C++ LamaHub Yes GNU GPL No 0.0.6.3 (2010-04-25) Unknown Unknown Unknown No C DC Sharp Hub Yes GNU GPL No 3.0.4 beta (2004-09-06) Unknown Unknown Unknown No C# NMDC hub FOSS Software license Active Latest version (release date) GUI CLI Other IPv6 support Programming language Based on
Operating system support
NMDC hub Windows Linux Mac OS X Other UFOHub Yes No No No Eximius Yes No No No PTDCH Yes No No No Aquila Yes Yes No No Dtella Yes Yes Yes No HeXHub Yes No No No Open Direct Connect Hub No Yes No OpenWrt Flexhub Yes Yes No No openDCd Yes Yes No No DDCH DevDirect Connect Hub Yes No No No DBHub No Yes No No PtokaX Yes Yes No FreeBSD, Nexenta py-dchub Yes Yes Yes Any Python compatible platform RusHub Yes Yes No FreeBSD VerliHub No Yes No No Yhub Yes No No No Ynhub Yes No No No xHub Yes Yes No No LamaHub Yes Yes Yes OS/2, OpenBSD, NetBSD, PC-BSD, FreeBSD, ZeX/OS DC Sharp Hub Yes No No No NMDC hub Windows Linux Mac OS X Other
While not mandated by the protocol, most clients send a "tag". This is part of the client's description and display information ranging from client name and version to number of total available slots to if the user is using a proxy server. It was originally added to DC++, due to its ability to be in multiple hubs with the same instance. The information is arbitrary. The original client's file list (a comprehensive list of the files a user shares) was compressed using Huffman's compression algorithm. Newer clients (among them DC++) serve an XML-based list, compressed with bzip2.
NMDC Client FOSS Software license Active MLDonkey Yes GNU GPL Yes Shareaza Yes GNU GPL Yes NeoModus Direct Connect No Proprietary
No ShakesPeer Yes GNU GPL No Valknut Yes GNU GPL No DCTC Yes GNU GPL No DC# Yes GNU GPL No LDCC Unknown Unknown No DCDM++ Yes GNU GPL No fulDC Yes GNU GPL No RevConnect Yes GNU GPL No CzDC Yes GNU GPL Yes EiskaltDC Yes GNU GPL No NMDC Client FOSS Software license Active
Operating system support
NMDC Client Windows Linux Mac OS X Other MLDonkey Yes Yes Yes No Shareaza Yes No No No NeoModus Direct Connect Yes Yes No No ShakesPeer No No Yes No Valknut No Yes No FreeBSD DC# Yes No No No LDCC No Yes No No DCDM++ Yes No No No fulDC Yes No No No RevConnect Yes No No No CzDC Yes No No No EiskaltDC No Yes No FreeBSD NMDC Client Windows Linux Mac OS X Other
Interface and programming
NMDC Clients GUI CLI Other Programming language Based on MLDonkey Yes Yes WebUI Objective Caml, C, assembly Shareaza Yes Unknown Unknown C++ NeoModus Direct Connect Yes No No Visual Basic, C++ ShakesPeer Yes No No C Valknut Yes No No C++ DCTC No No Yes C++ DC# Yes No No C# LDCC No No Yes C DCDM++ Yes No No C++ DC++ fulDC Yes No No C++ DC++ RevConnect Yes No No C++ DC++ CzDC Yes No No C++ DC++ EiskaltDC Yes No No C++ Valknut NMDC Clients GUI CLI Other Programming language Based on
Hub linking software links hubs' main chat, so that users can see and respond to chat that is in a hub they're not directly connected to. Often used to draw in users to hubs, or make private or small hubs more widely known. Where as advertising a hub is "frowned upon" and is usually repercussion with floods or denial of service attacks, forming a more or less formal network by means of linking hub chat is a legitimate means for getting free publicity. Some Hub programs are able to support a more advanced form of linking which includes all the normal functions, chat, private messages, search and file transfers between users on different hubs can be supported through hub specific solutions or hub software neutral extensions using scripts/plug-ins.
Other software Software type FOSS Software license Active jDCBot General library Yes GNU GPL Yes Net::DirectConnect General library Yes Unknown Yes FlowLib General library Yes GNU GPL Yes DC-hublink Link Yes GNU GPL No Hub-Link Link Yes GNU GPL No MyIrcDcLinks Link Yes GNU GPL Yes NetChatLink Link Yes GNU GPL Yes Kitty Bot Yes GNU GPL No Other software Software type FOSS Software license Active
Operating system support
Other software Windows Linux Mac OS X Other jDCBot Yes Yes Yes Any Java compatible platform Net::DirectConnect Yes Yes Yes Any Perl compatible platform FlowLib Yes Yes Yes Any C# compatible platform DC-hublink Yes No No No Hub-Link Yes No No No MyIrcDcLinks Yes No No No NetChatLink Yes No No Runs under WINE Kitty Yes No No No Other software Windows Linux Mac OS X Other
Interface and programming
Other software GUI CLI Other Programming language Based on jDCbot No No No Java Net::DirectConnect No No No Perl FlowLib No No No C# DC-hublink Yes No No Visual Basic Hub-Link Yes No No Visual Basic MyIrcDcLinks Yes No No Delphi NetChatLink Yes No No Delphi Kitty Unknown Unknown Unknown C# Other software GUI CLI Other Programming language Based on
Name NMDC ADC Active Registration CTM Detection Active dchublist.com/ Yes Yes Yes Webbased Yes Yes openhublist.org Yes Yes Yes Webbased Yes Yes publichublist.nl Yes No Yes Regserver Unknown Yes hublist.org.nz Yes Yes Yes Webbased Unknown Yes dchublist.ru Yes No Yes Unknown Unknown Yes qsdchublist.com Yes No Yes Webbased Yes Yes Name NMDC ADC Active Registration CTM Detection Active
Direct Connect used for DDoS attacks
As the protocol allow hubs to redirect users to another hub, malicious hubs have redirected users to other places than real Direct Connect hubs, effectively causing a Distributed Denial of Service attack. As well, the hubs may alter the IP in client to client connections, pointing to a potential victim.
The CTM Exploit made its presence known during 2006-2007; it made the developers take security issues more seriously since the whole direct connect network suffered from DDoS attacks from this exploit. It's recommended for users to run later versions of the hub software due to this exploit. Many hublists have started to block insecure hubs.
- ^ Annalee Newitz (July 2001). "Sharing the Data". Metro, Silicon Valley's Weekly Newspaper. Metro Publishing Inc. http://www.metroactive.com/papers/metro/07.12.01/work-0128.html. Retrieved 2006-10-16.
- ^ Fredrik Ullner (April 2007). "Command and bandwidth estimations in NMDC". DC++: Just These Guys, Ya Know?. http://dcpp.wordpress.com/2007/04/23/command-and-bandwidth-estimations-in-nmdc/. Retrieved 2007-07-27.
- ^ cologic (August 2007). "CTM tokens in ADC (or why the NMDC protocol is terrible, part 2)". DC++: Just These Guys, Ya Know?. http://dcpp.wordpress.com/2007/08/03/ctm-tokens-in-adc-or-why-the-nmdc-protocol-is-terrible-part-2/. Retrieved 2007-10-07.
- ^ Todd Pederzani (June 2006). "Filtering Redux". DC++: Just These Guys, Ya Know?. http://dcpp.wordpress.com/2006/06/04/filtering-redux/. Retrieved 2007-08-31.
- ^ http://dtella.org/changelog
- ^ http://www.ptokax.org/news.html
- ^ http://sourceforge.net/projects/rushub/files/RusHub/
- ^ Paul Sop (May 2007). "Prolexic Distributed Denial of Service Attack Alert". Prolexic Technologies Inc.. Prolexic Technologies Inc.. Archived from the original on 2007-08-03. http://web.archive.org/web/20070803175513/http://www.prolexic.com/news/20070514-alert.php. Retrieved 2007-08-22.
- ^ Robert Lemos (May 2007). "Peer-to-peer networks co-opted for DOS attacks". SecurityFocus. http://www.securityfocus.com/news/11466. Retrieved 2007-08-22.
- ^ Fredrik Ullner (May 2007). "Denying distributed attacks". DC++: Just These Guys, Ya Know?. http://dcpp.wordpress.com/2007/05/22/denying-distributed-attacks/. Retrieved 2007-08-22.
- ^ Jan Vidar Krey (February 2009). "Referral extension". DC++ Launchpad Page. https://bugs.launchpad.net/dcplusplus/+bug/316096. Retrieved 2009-02-11.
- ^ Jan Vidar Krey (February 2009). "Referral extension on ADCPortal wiki". ADCPortal.com. http://www.adcportal.com/wiki/index.php/REF. Retrieved 2009-02-11.
- ^ Eugen Hristev (February 2009). "DC++ pointing out the corrupted". DC++: Just These Guys, Ya Know?. http://dcpp.wordpress.com/2009/02/11/dc-pointing-out-the-corrupted/. Retrieved 2009-02-11.
- ^ Toast (January 2009). "CTM Review and the errors of past". ADCPortal. http://www.adcportal.com/forums/viewtopic.php?f=10&t=431&start=0. Retrieved 2009-01-27.
- ^ Fredrik Ullner (July 2011). "Long lost response regarding DC being used as a DDoS tool". DC++: Just These Guys, Ya Know?. https://dcpp.wordpress.com/2011/07/20/long-lost-response-regarding-dc-being-used-as-a-ddos-tool/. Retrieved 2011-07-20.
- NMDC Protocol Wiki (Mirror)
- NMDC Protocol Document
- NMDC Protocol (No files to view/download?)
- NMDC Protocol Wiki (Doesn't work - expired domain as of Aug 2011. at least)(website transferred)
Peer-to-peer file sharing Networks and protocolsCentralizedDecentralized Comparisons of clients Hyperlinks Uses Concepts
Wikimedia Foundation. 2010.
Look at other dictionaries:
Direct connect — may refer to: Direct Connect (file sharing), a file sharing client and protocol A protocol used by the program AOL Instant Messenger A push to talk system similar to a walkie talkie, first marketed by Sprint Nextel A standardized XML based… … Wikipedia
Direct Connect — (DC) ist ein Peer to Peer Protokoll, außerdem der Name eines Computerprogramms, welches dieses Protokoll implementiert. Schließlich wird auch das Filesharing Netzwerk, welches die Benutzer durch ihre Teilnahme aufbauen, als Direct Connect… … Deutsch Wikipedia
File-Sharing — Mit Filesharing (deutsch Dateifreigabe oder gemeinsamer Dateizugriff, wörtlich Dateien teilen) bezeichnet man das direkte Weitergeben von Dateien zwischen Benutzern des Internets unter Verwendung eines Peer to Peer Netzwerks. Dabei befinden sich… … Deutsch Wikipedia
File Sharing — Mit Filesharing (deutsch Dateifreigabe oder gemeinsamer Dateizugriff, wörtlich Dateien teilen) bezeichnet man das direkte Weitergeben von Dateien zwischen Benutzern des Internets unter Verwendung eines Peer to Peer Netzwerks. Dabei befinden sich… … Deutsch Wikipedia
File sharing — Mit Filesharing (deutsch Dateifreigabe oder gemeinsamer Dateizugriff, wörtlich Dateien teilen) bezeichnet man das direkte Weitergeben von Dateien zwischen Benutzern des Internets unter Verwendung eines Peer to Peer Netzwerks. Dabei befinden sich… … Deutsch Wikipedia
Comparison of file sharing applications — File sharing is a method of distributing electronically stored information such as computer programs and digital media. Below is a list of file sharing applications. Top A B C D E F G H I J K L M N O P Q R S T U V … Wikipedia
Peer-to-peer file sharing — Part of a series on File sharing Technologies … Wikipedia
Advanced Direct Connect — (ADC) is a peer to peer file sharing protocol, based on the topology of the Direct Connect (DC) protocol. ADC clients connect to a central hub and can download files directly from one user to another.Hubs feature a list of clients or users… … Wikipedia
NeoModus Direct Connect — was a file sharing client for Windows and Mac users that provided file sharing capabilities for any type of file within a hub centric, peer to peer network and contained adware. History NeoModus operated from the years 2000 and 2005. Along with… … Wikipedia
Direct cable connection — For other uses, see DCC (disambiguation). Direct Cable Connection (DCC), is a feature of Microsoft Windows that allows a computer to transfer and share files (or connected printers) with another computer, via a connection using either the serial… … Wikipedia