zhangyang-libzt/docs/walkthrough.md

Walkthrough

In this document we'll run through a simple example which should demonstrate the concept of the ZeroTier SDK. For this tutorial you'll need two devices (or at least the ability to run a VM or something like Docker). We will demonstrate a simple TCP server application intercepted on linux. This is only one of many ways the SDK can be used, but it'll at least convey the core concept how how the intercept works.

On your first device:

• Download ZeroTier at zerotier.com
• Install it on a device/computer
• Create an account and new virtual network at my.zerotier.com
• Join your device to the network and assign it an address zerotier-cli join <nwid>
• Use zerotier-cli listnetworks to verify that you've joined the network.

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On your second device:

Build the SDK

make linux SDK_PICOTCP=1 SDK_IPV4=1 SDK_DEBUG=1; make -s check; ls -lG build

Build test apps

make tests

Start the SDK service in the background

./zerotier-cli -U -p8000 /netpath &

Set environment variables

export ZT_NC_NETWORK=/netpath/nc_XXXXXXXXXXXXXXXX
export LD_PRELOAD=./libztintercept.so

Where netpath can be any path you'd like the client's keys and configuration to be stored and XXXXXXXXXXXXXXXX is the 16-digit network ID.

Start your app

./build/tests/linux.tcpserver4.out 8001

Now, on your first device, ./build/tests/linux.tcpclient4.out <ip> 8001 where <ip> is the ip address that you assigned to your first device.

Now, you'll note that your new TCP server is automatically intercepted and available at on port 8001. The tcpclient4 sample app running on the device with a normal instance of ZeroTier running will be able to connect directly to your intercepted tcpserver4 app on the second machine running the SDK.

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You've just uplifted your app onto your private ZeroTier network.