You can use this repo to install the nettica-client and nettica.agent for Debian Linux distributions. This repo will install nettica for amd64, arm64, and armhf (32-bit raspberry pi) architectures.

Resolvconf is needed for WireGuard DNS functionality. Iptables is needed for subnet routing and not installed by default on some newer Debian distros. Rdesktop enables RDP functionality in the nettica agent.

# Add the Nettica GPG key to be used by apt
sudo apt update
sudo apt install curl -y
sudo curl -s -o /etc/apt/sources.list.d/nettica.list https://ppa.nettica.com/nettica.list
curl https://ppa.nettica.com/nettica.gpg | sudo gpg -o /usr/share/keyrings/nettica.gpg --dearmor --batch --yes
sudo apt update

# Install wireguard if not already installed
sudo apt install wireguard-tools iptables -y

# Install nettica-client
sudo apt install nettica-client -y

# Set the Nettica device config
# Create a device on https://my.nettica.com and copy and paste the config url text
# See https://nettica.com/adding-a-device-manually
# This can be skipped if you're installing on a desktop and using nettica agent.
# curl "http://localhost:53280/config/?id=device-cciAg&apiKey=device-api-bu5WuXRq&server=https://my.nettica.com"

# Enable IP forwarding for subnet routing or VPN tunneling
# Enable packet forwarding for IPv4 and IPv6
sudo sed -i "s/#net.ipv4.ip_forward=1/net.ipv4.ip_forward=1/g" /etc/sysctl.conf
sudo sed -i "s/#net.ipv6.conf.all.forwarding=1/net.ipv6.conf.all.forwarding=1/g" /etc/sysctl.conf
sudo sysctl -p

# Install resolvconf.  This tends to break DNS until reboot, let's not do that by appending the
# original /etc/resolv.conf to the end of the new one, and make resolvconf update itself.
sudo apt install resolvconf -y
sudo ln -sf /etc/resolvconf/resolv.conf.d/original /etc/resolvconf/resolv.conf.d/tail
sudo resolvconf -u

If you're installing on a Linux Desktop, install the Nettica Agent as well:

# Install nettica agent
sudo apt install nettica.agent rdesktop
nettica.agent &