BIND response policy zones (RPZ) support provides a mechanism for
overriding the responses to DNS queries based on a wide range of
criteria. In the simplest form, a response policy zone can be used to
provide different responses to different clients, or "block" some DNS
names.
For the Pyrocufflink and related networks, I plan to use an RPZ to
implement ad/tracker blocking. The goal will be to generate an RPZ
definition from a collection of host lists (e.g. those used by uBlock
Origin) periodically.
This commit introduces basic support for RPZ configuration in the
*named* role. It can be activated by providing a list of "response
policy" definitions (e.g. `zone "name"`) in the `named_response_policy`
variable, and defining the corresponding zones in `named_zones`.
DHCP is provided by *dns1.pyrocufflink.blue* now, not the gateway. To
allow dynamic DNS updates from it, the correct source address must be
listed in the zone configuration for *pyrocufflink.red*.
Because *jenkins0.pyrocufflink.blue* runs Docker, it has an extra
virtual interface and IP address, for container communication. By
default, Samba registers all IP addresses in DNS, and cannot
differentiate between the actual interface and the Docker bridge. This
can cause other hosts to attempt to contact *jenkins0.pyrocufflink.blue*
using the wrong address.
The `samba_interfaces` variable controls the value of the `interfaces`
global configuration option for Samba. One of the things this option
controls is which addresses to register in DNS. By setting it to the
network address of the *pyrocufflink.blue* network, we can prevent the
virtual address from being used at all.
To avoid having a single point of failure, a second recursive DNS server
is necessary. This will be useful in cases where the VM hosts must both
be taken offline, but Internet access is still required.
The new server, *dns1.pyrocufflink.blue*, has all the same zones defined
as the original. It forwards the *pyrocufflink.blue* zone and
corresponding reverse zones to the domain controllers, and acts as a
slave for the *pyrocufflink.red* zone.
In order to support adding a second DNS server, the BIND zone
configuration needs to be partially modularized. While the forwarder
definitions for *pyrocufflink.blue*, etc. will remain the same, the
*pyrocufflink.red* zone will be different, as it will be a slave zone on
the second server. This commit breaks up the definition of the
`named_zones` variable into two parts:
* `pyrocufflink_red_zones`: This is a list of zone objects for
*pyrocufflink.red* and its corresponding reverse zone. On
*dns1.pyrocufflink.blue*, these are master zones. On the new server,
these will be slaves.
* `pyrocufflink_common_zones`: This is a list of zone objects for the
zones that are the same on both servers, since they are all forwarding
zones.
Similarly, the `named_keys` variable only needs to be defined on the
master, since DHCP will only send updates there.
*smtp1.pyrocufflink.blue* is a VM that will replace
*smtp0.pyrocufflink.blue*, a Raspberry Pi.
I decided that there is little use in having the availability guarantee of
a discreet machine for the SMTP relay. The only system that would NEED
to send mail if the VM host fails is Zabbix, which operates as its own
relay anyway. As such, the main relay can be a VM, and the Raspberry Pi
can be repurposed as a recursive DNS server.
The Management network (VLAN 10, 172.30.0.240/28) will be used for
communication with and configuration of network devices including
switches and access points. This keeps configuration separate from
normal traffic, and allows complete isolation of infrastructure devices.
The gateway device is now monitored by Zabbix. Adding it to the *zabbix*
group ensures that the Zabbix agent is installed and configured
correctly.
Because the *zabbix-agent* role has a task to configure FirewallD, the
`host_uses_firewalld` variable needs to be set to `false` for *gw0*,
since it does not use FirewallD.
The `gitea_root_url` variable is used to configure the root URL for
Gitea, which is in turn used to generate HTTP/HTTPS "clone" links for
Git repositories. If this value is not set, the default is used, which
does not work since the application is behind a reverse proxy.
This commit adjusts the firewall and networking configuration on dc0 to
host the Pyrocufflink remote access IPsec VPN locally instead of
forwarding it to the internal VPN server.
For internal services, particularly DNS, it is easier to use a ULA
prefix than rely exclusively on routed addresses, since these can change
relatively frequently.
The *filter* table is responsible for deciding which packets will be
accepted and which will be rejected. It has three chains, which classify
packets according to whether they are destined for the local machine
(input), passing through this machine (forward) or originating from the
local machine (output).
The *dch-gw* role now configures all three chains in this table. For
now, it defines basic rules, mostly based on TCP/UDP destination port:
* Traffic destined for a service hosted by the local machine (DNS, DHCP,
SSH), is allowed if it does not come from the Internet
* Traffic passing through the machine is allowed if:
* It is passing between internal networks
* It is destined for a host on the FireMon network (VPN)
* It was NATed to in internal host (marked 323)
* It is destined for the Internet
* Only DHCP, HTTP, and DNS are allowed to originate from the local
machine
This configuration requires an `internet_iface` variable, which
indicates the name of the network interface connected to the Internet
directly.
Dustin