Direct Connect glossary: DC terms explained

Short definitions of the terms and abbreviations you will meet across Direct Connect.

Network & hubs

Favorites: Hubs and users your client saves for quick access.
File list: The list of everything a user shares, which others browse to download.
Hub: The server where users meet, chat, and search. It coordinates but never carries files.
Hublist: A directory of public hubs your client can load.
Minimum share: The smallest share size a hub requires before you can join.
Search: Asking the hub to query everyone for files that match your terms.
Share: The files you offer to the network.
Slot: One upload connection. Hubs and clients limit how many run at once.

Active mode: Your client accepts incoming connections directly. Best for search and downloads.
Passive mode: Your client cannot accept incoming connections, for example behind NAT or a firewall. Limited.
Port forwarding: Opening a port on your router so other clients can reach you, which enables active mode.
UPnP: A router feature that can open ports automatically, used to set up active mode without manual forwarding.

ADC: Advanced Direct Connect, the modern protocol.
ADCS: ADC over TLS (encrypted).
CID / SID: In ADC, a client's permanent ID (CID) and its per-session ID (SID).
Magnet link: A link that points to a file by its hash.
NMDC: NeoModus Direct Connect, the original protocol.
NMDCS: NMDC over TLS (encrypted).
TTH: Tiger Tree Hash, the hash that identifies a file by its content.

Client: The program you use to connect, like DC++ or AirDC++.
DC++: The original open-source client and the basis for several others.
Leecher: Someone who downloads but shares little or nothing. Many hubs discourage this with a minimum share.
Operator (op): A user with moderation rights on a hub.
Private message (PM): A one-to-one chat with another user on a hub.