ADC protocol: the modern Direct Connect

ADC (Advanced Direct Connect) is the modern successor to NMDC. The idea is the same, the hub coordinates and clients transfer, but the design is cleaner: a clear message structure, real client identities (CID and SID), feature negotiation, and proper TLS support (ADCS). Setting something up fresh today? ADC is the saner pick.

Documentation

• ADC protocol documentation (maintained by the DC++ team)
• ADC-EXT documentation (maintained by the DC++ team)

HBRI

HBRI is an unofficial ADC extension for hybrid hubs that are reachable over both IPv4 and IPv6. It lets the hub verify the address a client did not connect with: the client opens a short second login connection over the other IP version and proves it with a token, so the hub can publish both addresses and keep client-to-client connections and NAT traversal working across both protocols.

It is implemented in AirDC++, ADCH++, and Luadch-ng but is not part of the official ADC specification. For the original proposal, the implementation notes, and an example login, see the discussion on our forum:

• HBRI: IPv4/IPv6 verification for hybrid hubs

For the older protocol, see NMDC.