# Creating a New Network

This guide is for those who wish to start a new isle network of their
own.

By starting a new isle network, you are becoming the administrator of a
network. Be aware that being a network administrator is not necessarily easy,
and the users of your network will frequently need your help in order to have a
good experience. It can be helpful to have others with which you are
administering the network, in order to share responsibilities.

## Requirements

Creating a network is done using a single host, which will become the first host
in the network.

The configuration used during network creation will be identical to that used
during normal operation of the host, so be prepared to commit to that
configuration for a non-trivial amount of time.

The requirements for this host are:

* A public static IP, or a dynamic public IP with [dDNS][ddns] set up.

  * There should be UDP port which is accessible publicly over that IP/DNS name.
    This may involve forwarding the UDP port in your gateway if the host is
    behind a NAT, and/or allowing traffic on that UDP port in your hosts
    firewall.

* At least 3 GB of disk storage space.

  * At least 3 directories should be chosen, each of which will be committing at
    least 1GB. Ideally these directories should be on different physical disks,
    but if that's not possible it's ok. See the Next Steps section.

* None of the resources being used for this network (the UDP port or storage
  locations) should be being used by other networks.

## Step 1: Configure the isle Daemon

Open `/etc/isle/daemon.yml` in a text editor and perform the following changes:

* Set the `vpn.public_addr` field to the `host:port` your host is accessible on,
  where `host` is the static public IP/DNS name of your host, and `port` is the
  UDP port which is publicly accessible.

* Configure 3 (at least) allocations in the `storage.allocations` section.

Save and close the file.

Run the following to restart the daemon with the new configuration:

```
sudo systemctl restart isle
```

## Step 2: Choose Parameters

There are some key parameters which must be chosen when creating a new network.
These will remain constant throughout the lifetime of the network, and so should
be chosen with care.

* Name: A human-readable name for the network. This will only be used for
  display purposes.

* Subnet: The IP subnet (or CIDR) will look something like `10.10.0.0/16`, where
  the `/16` indicates that all IPs from `10.10.0.0` to `10.10.255.255` are
  included. It's recommended to choose from the [ranges reserved for private
  networks](https://en.wikipedia.org/wiki/IPv4#Private_networks), but within
  that selection the choice is up to you.

* Domain: isle is shipped with a DNS server which will automatically
  configure itself with all hosts in the network, with each DNS entry taking the
  form of `hostname.hosts.domain`, where `domain` is the domain chosen in this
  step. The domain may be a valid public domain or not, it's up to you.

* Hostname: The hostname of your host, which will be the first host in the
  network, must be chosen at this point. You can reference the [Adding a Host to
  the Network](./adding-a-host-to-the-network.md) document for the constraints
  on the hostname.

* IP: The IP of your host, which will be the first host in the network. This IP
  must be within the chosen subnet range.

## Step 3: Create the Network

To create the network, run:

```
sudo isle network create \
    --name <name> \
    --ip-net <subnet> \
    --domain <domain> \
    --hostname <hostname>
```

At this point your host, and your network, are ready to go! To add other hosts
to the network you can reference the [Adding a Host to the Network][add-host]
document.

[add-host]: ./adding-a-host-to-the-network.md
[ddns]: https://www.cloudflare.com/learning/dns/glossary/dynamic-dns/