DC++ is a free and open-source, peer-to-peer file-sharing client that can be used to connect to the Direct Connect network or to the ADC protocol. It is developed primarily by Jacek Sieka, nicknamed arnetheduck.

As of 2005, no official statistics exist to verify the proportion of DirectConnect users using DC++. However, it is typically believed to be the most extensively used by a large margin; administrators of popular public DirectConnect hubs typically agree that DC++ is the client used by a significant majority.

DC++ is a free and open-source alternative to the original client, NeoModus Direct Connect (NMDC); it connects to the same file-sharing network and supports the same file-sharing protocol. One of the reasons frequently attributed to the aforementioned popularity of DC++ is that it has no adware of any kind, unlike NMDC .

Many other clients exist for the Direct Connect network, and most of these are DC++ "mods": modified versions of DC++, based on DC++'s source code. A partial list of DC++ mods is given below. Some of these clients were developed for specialized communities (e.g. music-sharing communities), or in order to support specific experimental features, or perhaps features that have been rejected from inclusion in DC++ itself. An example of an experimental feature is hashing, which was initially implemented in BCDC++ and later adopted by DC++.

Hub addresses

DC++ supports hub addresses in the following forms: dchub://example.com[:4012], with an optional port, and adc://example.com:12345. The dchub:// text designates a hub using the NMDC protocol whereas the adc:// designates an ADC protocol based hub. In the example, 4012 is the port where you can access the hub; the default port for NMDC hubs is 411.

Derivatives

An advantage of the free and open-source nature of DC++ is that several derivatives (mods) have been released which add features to the original client.

Many users send patches to DC++ which are included in future releases, but some features are rejected by the developer. Stated reasons for rejecting a patch are because they are coded poorly, or that the feature is frivolous, abusable or overly specialized, and does not belong in the main client. Examples include: upload bandwidth limiting (many users feel that upload bandwidth limiting is a form of cheating, while other users not using a full-duplex network connection can only achieve reasonable download speeds by limiting uploads), colorized chat, specialized operator functions (e.g. client/share checking).

The developers of some mods contribute features and bug-fixes back to DC++.

Below is a list of well-known mods and their features:

BCDC++

Features:

Automatic active mode IP configuration

Bandwidth limiting

Chat coloring (e.g. nickname highlighting)

Custom description (tag) setting and DC++ emulation

Lua scripting support

Winamp, MPlayerC and iTunes "Now Playing" messages (ability to use a command to send the current ly playing media file to the chat)

BCDC++

fulDC

This client is the spiritual successor of oDC.

Features:

Chat colorization (nick and custom highlighting)

Chat log rotation (deletion)

Popups on certain events (PM, hub disconnection)

Search enrichments in download queue

Total time left in transfer window

Skiplist for downloads and the share

Automatic refresh of incoming files and the share

Free slots file extensions

Max sources for match queue

Shortcuts to popular web sites through chat commands

http://www.fuldc.net/ - "fulDC is officially a dead project. I have lost interest in developing it further. Don't count on any new releases."

fulDC

LDC++

Features:

Skiplist for downloads and the share

Search skip files

Clear chat button in PM

Customizable tab style

Multiple selection of styles

Options to shutdown the PC upon completion of download

Shutdown button to force the PC to shut down

Password for favorite hubs obscured on disk

Checkbox in PM to enable or disable sound

Synchronization with NTP server

Suspend monitor

LDC++ (StrongDC++ mod with more features added, has not seen updates since 2005)

RevConnect

Features:

Segmented downloading

Kademlia

Partial File Sharing

Credit System

StrongDC++

Features:

Automated PC shutdown

Segmented downloading

Real upload queue

Balloon tips for events

Target folders by file type

Fake detector

Filter of search results

Chat emoticons

Tool for getting TTH of any file

Bandwidth limiting

Grouping search results by TTH

Customizable appearance

Display MP3 information before downloading

Partial File Sharing

Customizable Sounds

StrongDC++

ApexDC++

Based on StrongDC++ 2.

Features:

Peerguardian support

Automatic active mode IP configuration

Chat formatting (bold, italics, underlined)

Seed files to a hub with intelligent chunk spreading (super seeding)

Customizable appearance

Tray password protection

State what away messages are displayed at specified times

Permanently ignore users

Per-hub configuration

Segmented downloading

Bandwidth limiting

ApexDC++

LinuxDC++

LinuxDC++ on Linux/Gnome

LinuxDC++ is a Unix port that is based on the core of DC++. It has a rewritten user interface based on the GTK+ toolkit. Latest version is 1.0.1, released on 25 November 2007. It is being developed actively and is available through CVS. Even though the name implies it is Linux-only, it works on other POSIX compliant operating systems, such as NetBSD and FreeBSD.

CzDC

Features:

Automated PC shutdown

Bandwidth limiting

Chat coloring and formatting

Country flags in transfers and hublist

Customizable double click actions

File preview

Customizable appearance

Favorite hubs passwords encoding

Grouping search results by TTH.

Max sources for auto match queue

Pause and resume search

Ability to ignore users

CzDC

SababaDC

Features

Segmented downloading

Partial File Sharing

Auto search for alternates in background for even faster downloads

IE browser support

Drop slower downloads

Insert your IP automatically every 60 minutes

support web server

control traffic shaping - Avoid ISP P2P throttling

Transfer speed limit - with timer from 1-10 hours

Installs Skitu/Skipu Toolbar to Internet Explorer without a option to disable, but the author claims "No spyware, No adware, No trojan Horse, just the best file Sharing" SababaDC

Other mods

McDC++, features: changeable icons, changeable emoticons

DCDM++, based on BCDC++, an operator-specific client that tries to detect malevolent clients

DDC++, Icelandic DC client based on iDC++ [Community Quit]

IceDC++, based on ApexDC++, designed with Kiwis in mind, peerguardian plugin

LanDC++, mod for IceDC++, designed for LANs where hashing is not desirable

ApexDC++ Speed Mod, based on ApexDC++, extended functionality of "Favorite Users" page (limit upload speed for user, ignore PM, ban, etc). Project frozen.

iDC++, Operator Client, segmented downloading

More can be found on: DC++ FAQ: Windows clients