# 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 300 GB of disk storage space.

  * At least 3 directories should be chosen, each of which will be committing at
    least 100GB. 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: Create a `daemon.yml` File

A `daemon.yml` will need to be created for use during network creation. You can
create a new `daemon.yml` with default values filled in by doing:

```
isle admin create-network --dump-config > /path/to/daemon.yml
```

Open this file 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.

## 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: Prepare to Encrypt `admin.yml`

The `admin.yml` file (which will be created in the next step) is the most
sensitive part of an isle network. If it falls into the wrong hands it can be
used to completely compromise your network, impersonate hosts on the network,
and will likely lead to someone stealing or deleting all of your data.

Therefore it is important that the file remains encrypted when it is not being
used, and that it is never stored to disk in its decrypted form.

This guide assumes that you have GPG already set up with your own secret key,
and that you are familiar with how it works. There is no requirement to use GPG,
if you care to use a different method.

## Step 4: Create the `admin.yml` File

To create the `admin.yml` file, which effectively creates the network itself,
you can run:

```
sudo isle admin create-network \
    --config-path /path/to/daemon.yml \
    --name <name> \
    --ip-net <ip/subnet-prefix> \
    --domain <domain> \
    --hostname <hostname> \
    | gpg -e -r <my gpg email> \
    > admin.yml.gpg
```

A couple of notes here:

* The `--ip-net` parameter is formed from both the subnet and the IP you chose
  within it. So if your subnet is `10.10.0.0/16`, and your chosen IP in that
  subnet is `10.10.4.20`, then your `--ip-net` parameter will be `10.10.4.20/16`.

* Only one gpg recipient is specified. If you intend on including other users as
  network administrators you can add them to the recipients list at this step,
  so they will be able to use the `admin.yml` file as well. You can also
  manually add them as recipients later.

You will see a lot of output, as `create-network` starts up many child processes
in order to set the network up. It should exit successfully on its own after a
few seconds.

At this point you should have an `admin.yml.gpg` file in your current directory.

## Step 5: Run the Daemon

The isle daemon can be run now, using the following command:

```
sudo isle daemon -c /path/to/daemon.yml
```

**NOTE** that you _must_ use the same `daemon.yml` file used when creating the
network for the daemon itself.

At this point your host, and your network, are ready to go! You can reference
the [Getting Started](../user/getting-started.md) document to set up your
host's daemon process in a more permanent way.

[ddns]: https://www.cloudflare.com/learning/dns/glossary/dynamic-dns/