# CAcert DNS zones

CAcert runs its own public DNS nameservers on ns1 and ns2 in its BIT datacenter
rack in Ede.

We use [PowerDNS](https://doc.powerdns.com/authoritative/index.html) installed
on Debian systems.

This repository contains a Python script `update-zones.py` that is used for
updating DNS information from this Git repository.

The canonical URL for this repository is
[https://code.cacert.org/critical/dns-zones.git](https://code.cacert.org/critical/dns-zones.git).

## Prerequisites

The server certificate for https://code.cacert.org/ needs to be trusted.
Therefore the CAcert root CA certificate needs to be put into
`/usr/local/share/ca-certificates` and hast to be registered as trusted by
running

```shell
update-ca-certificates
```

The `update-zones.py` script needs `git`, `pdnsutil` and `python3`. We only use
the Python 3 standard library and no external dependencies. The script uses
`/usr/lib/sendmail` to send change mails. Mail sending has been tested with
ssmtp and exim4.

To make sure that all these prerequisites are met, you may run

```shell
apt install python3 ca-certificates pdns-server git mail-transport-agent
```

## Cloning the repository

The git configuration on ns1 and ns2 has been adapted to allow remembering the
credentials to clone the repository. A separate user pdnssync has been setup to
allow cloning the repository.

This repository is meant to be cloned on the CAcert DNS servers ns1 and ns2.

```shell
cd ~
git config --global credential.helper store
git config --global pull.ff only
git clone https://code.cacert.org/critical/dns-zones.git
```

Credentials will only be asked for the initial clone. The credential helper
records them in in `~/.git-credentials`.

## Updating zones

The user running the update needs read access to the configuration in
`/etc/powerdns` (either member of the pdns group or root).

```
$ cd ~/dns-zones
$ git pull
$ ./update-zones.py
```

The `update-zones.py` tracks the local status in a branch (default
'provisioned') that is updated when

* a) zone changes have been applied
* b) the running PowerDNS is responsible as secondary nameserver

The `update-zones.py` script should be run on both nameservers.