Installing ZeroTier in Kali Linux

curl -s | sudo bash

You will then get this error:

*** Enabling and starting ZeroTier service...
Synchronizing state of zerotier-one.service with SysV service script with /usr/lib/systemd/systemd-sysv-install.
Executing: /usr/lib/systemd/systemd-sysv-install enable zerotier-one
System has not been booted with systemd as init system (PID 1). Can't operate.
Failed to connect to bus: Host is down
*** Package installed but cannot start service! You may be in a Docker
*** container or using a non-standard init service.

It will complain about some package named

└─$ service zerotier-one restart
Restarting ZeroTier One: zerotier-oneStopping ZeroTier One: zerotier-one.
Starting ZeroTier One: zerotier-one/usr/sbin/zerotier-one: error while loading shared libraries: cannot open shared object file: No such file or directory

So just get it installed:

sudo dpkg -i libssl1.1_1.1.1f-1ubuntu2_amd64.deb

Start the service:

└─$ sudo service zerotier-one start
Starting ZeroTier One: zerotier-one.

Connect to your network:

sudo zerotier-cli join NETWORK_ID
200 join OK