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Same network

When collaborators are on the same local network - an office LAN, a newsroom Wi-Fi, a hotel room with two laptops - DeepState connects the machines directly. Nothing goes further than the router, there is nothing to set up, and changes arrive as fast as you make them.

Turning it on​

In the board's Collaborate dialog, under Same network, click Turn on. Do this on every device that should take part; each also needs the board's key (from the invite code). The dialog shows Looking for colleagues on this network… until a peer is found, then lists each device with a green dot once the two sides have authenticated.

To join a board you don't have yet: Join shared board… → paste the code → Same network. The board appears as soon as any device with it comes into range.

How it works​

  • Every device announces itself by multicast on the local network every few seconds: its device ID, a TCP port it listens on, and a fingerprint of each board key it has enabled for network sync. The fingerprint is a hash - it reveals nothing about the key or the board.
  • When two devices see they hold a board with the same fingerprint, one of them opens a TCP connection to the other (deterministically, so both don't dial at once).
  • They exchange a mutual proof of the key: each sends a random nonce and expects it back encrypted under the board key. A device without the key cannot pass this step, and a device on the network that isn't part of the share learns nothing beyond "someone has a board".
  • From then on every frame on the connection is encrypted with the board key. The devices compare what each has seen from every author, send each other the difference, exchange any media files the other is missing, and then stay connected: new local changes are pushed within a couple of seconds.
  • Peers that stop announcing for 15 seconds are treated as gone and reconnected when they return.

Requirements and limits​

  • Both devices on the same IPv4 network segment with multicast allowed. Home and small office networks are fine. Many enterprise and guest Wi-Fi networks block multicast or isolate clients from each other ("AP isolation"); on those, use the relay.
  • The firewall on each machine must allow DeepState to listen on a TCP port and to receive UDP on port 47777. Windows asks the first time; on macOS, allow incoming connections when prompted.
  • VPNs usually break multicast discovery. Disconnect the VPN, or use the relay.
  • Discovery is IPv4 only.

Behaviour when peers are absent​

Nothing is queued anywhere: when a peer is away, the changes simply stay in your log, and the next time you are on the same network the two devices reconcile from where they left off. If your team is sometimes together and sometimes remote, enable both Same network and the relay; whichever is available carries the traffic.

Troubleshooting​

  • Never finds the other device. Check both are on the same Wi-Fi (not one on guest Wi-Fi), neither is on a VPN, and both have the board turned on for the network. Corporate networks: ask IT whether multicast/mDNS traffic is permitted between clients, or use the relay.
  • Found but never connects. A firewall is blocking the TCP connection. Allow DeepState through, or temporarily allow all incoming connections for the app.
  • Connected but nothing arrives. Both devices have the board enabled but hold different keys
    • one of you joined with an old invite code from before the key was regenerated. Stop sharing on the joining device, forget the key, and rejoin with the current code.