# Installation of gateway system

> Install Debian image for use as gateway for private network

Download a suitable system image
and load it onto the target computer box.

Start the box,
log in and finalize system-setup,
include some addons,
and enjoy your pure Debian gateway system.


## Preparations

### Hardware

System requires a computer in a box box and with power supply,
an additional network adapter,
and a microSD chip:

  * Box - [OLinuXino A20 LIME2][] or [OLinuXino A20 LIME][]
  * USB network adapter - preferably 1 Gbit/s USB3
  * MicroSD card - preferably speed rated "A1" or "A2", size 2GB is enough

[OLinuXino A20 LIME2]: <https://www.olimex.com/wiki/A20-OLinuXino-LIME2>
  "Olimex OLinuXino A20 LIME2"

[OLinuXino A20 LIME]: <https://www.olimex.com/wiki/A20-OLinuXino-LIME>
  "Olimex OLinuXino A20 LIME"


## Get and install image

Follow the guide at <https://box.redpill.dk/>.

Finalize setup of the system:

    sudo system-setup


### Turn system into a network gateway

Enable addon:

    sudo box-add-gateway

System is now configured like this:

  * Built-in network adapter requests address via DHCP, and expects an internet connection
  * Each USB adapter has a static private address, and serves DHCP to a private network

If above is what you want
then you are done!


### Static public IP

To use a fixed IP address for the built-in public-facing interface,
first copy the file `/etc/systemd/network/90-dhcp.network`
to `/etc/systemd/network/10-eth0.network`,
then adapt the copy as needed,
and finally restart network service.

Example:

    cp /etc/systemd/network/90-dhcp.network /etc/systemd/network/10-eth0.network
    nano /etc/systemd/network/10-eth0.network
    # Under [Match] change "Name":
    #   Name=eth0
    #
    # Under [Network] replace "DHCP" with "Address", "Gateway" and "DNS"
    #
    # Quit nano with CTRL+x and agree to save changes under proposed name
    service systemd-networkd restart


### Multiple internet connections

When you have more than one internet connection,
first identify the system device name of the interface,
then copy the file `/etc/systemd/network/90-dhcp.network`
to `/etc/systemd/network/10-XXX.network` (replace XXX with device name),
then adapt the copy as needed (as minimum set Name to match device name),
and finally restart network service.

Example:

    networkctl
    # notice device name
    cp /etc/systemd/network/90-dhcp.network /etc/systemd/network/10-enx00e04c688416.network
    nano /etc/systemd/network/10-enx00e04c688416.network
    # Under [Match] change "Name":
    #   Name=enx00e04c688416
    #
    # Under [Network] replace "DHCP" with "Address", "Gateway" and "DNS"
    #
    # Quit nano with CTRL+x and agree to save changes under proposed name
    service systemd-networkd restart


### Custom private network

If you want a custom configuration for a private network,
e.g. a specific static address or specific DHCP pool setup,
first identify the system device name of the interface,
then copy file `/etc/systemd/network/80-masq-dhcpserver.network`
to `/etc/systemd/network/10-XXX.network` (replace XXX with device name),
then adapt the copy as needed (as minimum set Name to match device name),
and finally restart network service.

Example:

    networkctl
    # notice device name
    cp /etc/systemd/network/80-masq-dhcpserver.network /etc/systemd/network/10-enx00095be2dfe2.network
    nano /etc/systemd/network/10-enx00095be2dfe2.network
    # Under [Match] change "Name":
    #   Name=enx00095be2dfe2
    #
    # Under [Network] change "Address":
    #   Address=192.168.2.1/24
    #
    # Under section [DHCPServer] change "PoolSize":
    #   PoolSize=200
    #
    # Quit nano with CTRL+x and agree to save changes under proposed name
    service systemd-networkd restart