Netboard

Netboard is a client/server application that allows to share your clipboard between different devices. It works by deploying a server, then running client on your devices to sync the clipboard.

The server uses websockets or chunked http encoding to push data to client, and while it is easier to handle the client part with the netboard client, it's perfectly possible to integrate it with anything else, like good old curl.

NOTE: netboard is NOT multi tenant. While it is possible to add it if there is any interest in the matter, for now it just assumes that anyone connecting with a valid certificate is willing to get its clipboard synchronized with the rest of the instance.

Installation

Getting the software

Using Go:

go install github.com/primalmotion/netboard@latest

The software is also packaged for Arch Linux and derivatives from the AUR:

yay -S netboard

Alternatively, if you want to use latest and greatest:

yay -S netboard-git

Certificates

Netboard uses mutual TLS to authenticate the clients. This is not optional, and you must generate several certificates:

• one certificate for the server (https)
• one certificate authority for the clients
• as many client certificates signed by the CA as you have devices.

You can generate certificates with the tool you like. This example will use tg.

First, we will generate the server certificate. You need to know in advance the hostname or IP the server will use.

tg cert --name netboard-server --dns my.netboard.com --ip 127.0.0.1

NOTE: You can sign that certificate with a CA you maintain, or get a certificate from let's encrypt.

Then we will create the CA needed to authenticate the users:

tg cert --is-ca --name netboard-client-ca

And finally client certificates:

tg cert \
  --signing-cert netboard-client-ca-cert.pem \
  --signing-cert-key netboard-client-ca-key.pem \
  --auth-client \
  --name my-laptop

tg cert \
  --signing-cert netboard-client-ca-cert.pem \
  --signing-cert-key netboard-client-ca-key.pem \
  --auth-client \
  --name my-phone

NOTE: don't reuse the same certificate over several devices as the fingerprint will be used to prevent sending back data you just sent, resulting in a update larsen.

Server

Copy over the netboard-server-cert.pem and netboard-server-key.pem, as well as the netboard-client-ca-cert.pem to the machine hosting the server. We will put them in /etc/netboard. Then write a config.yaml file with the following content:

server:
  cert: /etc/netboard/netboard-server-cert.pem
  key: /etc/netboard/netboard-server-key.pem
  client-ca: /etc/netboard/netboard-client-ca-cert.pem

Then run the server:

netboard server

Clients

Copy the client certificate to the appropriate devices, in ~/.config/netboard, then write a config.yaml file with the following content:

listen:
  url: https://my.netboard.com:8989
  cert: $HOME/.config/netboard/my-laptop-cert.pem
  cert-key: $HOME/.config/netboard/my-laptop-key.pem

Then run the client:

netboard listen

Repeat the process for every other clients you want to have all their clipboard synced.

Clipboard management modes

The netboard client can run using 2 modes, controlled by the --mode flag:

• lib: Uses native clipboard management libraries. This requires CGO and only works partially under Wayland
• wl-clipboard: Uses wl-copy and wl-paste utilities to handle the clipboard. This only works under Wayland.

More modes may come, as well as a smart way to choose the best for the current platform.

Clipboard listening mode

You can choose to use either chunked HTTP encoding (--websocket false) or websockets (--websocket true, the default). Websocket should offer better and faster pushes and connectivity loss detection.

Usage

Main command

$ netboard --help
Simple and secure network clipboard sharing engine

Usage:
  netboard [flags]
  netboard [command]

Available Commands:
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  listen      Sync data between clipboard and server
  server      Run the server

Flags:
  -h, --help      help for netboard
      --version   Show version

Use "netboard [command] --help" for more information about a command.

Server command

$ netboard server --help
Run the server

Usage:
  netboard server [flags]

Flags:
  -c, --cert string            path to the server public key
  -k, --cert-key string        path to the server private key
  -p, --cert-key-pass string   optional server key passphrase
  -C, --client-ca string       path to the client certificate CA
  -h, --help                   help for server
  -l, --listen string          The listen address of the server (default ":8989")

Listen command

$ netboard listen --help
Sync data between clipboard and server

Usage:
  netboard listen [flags]

Flags:
  -c, --cert string            Path to the client public key
  -k, --cert-key string        Path to the client private key
  -p, --cert-key-pass string   Optional client key passphrase
  -h, --help                   help for listen
      --insecure-skip-verify   Skip server CA validation. this is not secure
      --mode string            Select the mode to handle clipboard. wl-clipboard or lib (default "wl-clipboard")
  -C, --server-ca string       Path to the server certificate CA
  -u, --url string             The address of the netboard server (default "https://127.0.0.1:8989")
  -w, --websocket              Use websockets instead of chunked encoding (default true)