## Multi-box Delta Chat setup

This document details the requirements and setup needed to allow exchanging messages between Delta Chat instances
running on different boxes connected together over LAN.
This requires a few configuration changes.

## Requirements

- A way to access the boxes via console, either by using a keyboard and monitor, or by enabling
the SSH setting through the admin portal and connecting via SSH.
- The boxes must be configured with different hostnames, e.g., butterbox.local and jambox.local.
The hostname can only be changed at the time of the initial admin setup for a box.
- The boxes must be connected together in the same LAN, either by being plugged into the same router, or
by reconfiguring one of them to be a client of the hotspot provided by the other.
- The rest of the instructions assume the router provides the boxes with IP addresses via DHCP.

## MDNS Setup
- After making sure the boxes are on the same network, check they can resolve each other's local names,
by running an MDNS lookup command (`avahi-resolve -n -4 <name.local>`) on one of the boxes for the hostname of the others. The following 
example shows the address of `jambox.local` being resolved on the console of the box named `butterbox.local`:
```
root@butterbox:~# avahi-resolve -n -4 jambox.local

jambox.local	192.168.1.2
```

- If the above does not work, it could be due to a variety of reasons, the most likely being that the
router used to connect the boxes does not support forwarding MDNS queries. 
In this case, run the command `ip a` to find the local `eth0` address for each box, and then add 
that into the `/etc/hosts` file on the other boxes. This will allow them to find each other by hostname. 
For example, if `jambox.local` had an address of `192.168.1.2`, you would need to add the following
line to `/etc/hosts` on `butterbox.local`:

```192.168.1.2     jambox.local```

- In this example, the corresponding config change would also need to be made for any other connected boxes, e.g., jambox.local's `/etc/hosts` file.

## Nginx setup
- Edit the `/etc/nginx/sites-enabled/default` file to add an entry for `/mxdeliv` that points to
localhost, port 8081, on all boxes participating in the setup:

```angular2html

        location /mxdeliv {
                    proxy_pass http://127.0.0.1:8081;
                   }
```

## Testing

With the changes above, each box should be able to find the other boxes for mail delivery,
with incoming mail routed by `nginx` to the `madmail` service.
To test, create Delta Chat accounts on each box, and send test messages between them.