The ungleich DNS infrastructure » History » Revision 23
Revision 22 (Nico Schottelius, 03/26/2020 07:50 PM) → Revision 23/27 (Nico Schottelius, 01/11/2021 12:03 PM)
h1. The ungleich DNS infrastructure
{{toc}}
h2. Status
This document is *IN PRODUCTION*.
h2. SEE ALSO
* [[The_ungleich_network_infrastructure]]
h2. Overview
| | *place4* | *place5* | *place6* |
| *DNS64 prefix* | - | 2a0a:e5c0:0:1::/96 | 2a0a:e5c0:2:10::/96 |
| *DNS resolver* | - | 2a0a:e5c0:0:a::a 2a0a:e5c0:0:a::b | 2a0a:e5c0:2:a::a 2a0a:e5c0:2:a::b |
| (NAT64 enabled | | | |
| for certain networks) | | | |
| | | | |
| *DNS64 resolvers* | - | - | unbound1.place6.ungleich.ch (2a0a:e5c0:2:12:0:f0ff:fea9:c451) |
| | | | unbound2.place6.ungleich.ch (2a0a:e5c0:2:12:0:f0ff:fea9:c45d) |
| *DNS auth BIND* | dns1.ungleich.ch | dns2.ungleich.ch | dns3.ungleich.ch |
| | 2a01:4f8:150:7092::2 | 2a0a:e5c0::1 | 2a0a:e5c0:2:1::7 |
| | 176.9.50.202 | 185.203.112.1 | 185.203.114.1 |
| *DNS auth KNOT* | - | dns7.ungleich.ch | dns6.ungleich.ch |
* Every place has 2 redundant caching nameservers.
* All zones have 3 authorative nameservers, located in 3 different places
* Important zones (like ungleich.ch) need to be resolvable, even if a place goes offline
** For this reason some authorative data needs to be on the caching name servers
** For this reason we stay with a bind9 based setup for the moment (might change in the future)
h2. Architecture
In total we are running 5 servers that are responsible for caching and authorative answers:
* Authorative
** 1x server in place4 (bind)
** 1x VRRP IP of routers in place5 (bind)
** 1x VRRP IP of routers in place6 (bind)
* Caching
** 2x server ip of router in place5 (bind)
** 2x server ip of router in place6 (bind)
h2. How to update the ungleich DNS servers
To update all servers, use:
<pre>
cdist config d{1..7}.ungleich.ch
</pre>
| | | "virtual" | Note |
| d1 | router1.place5 | dns2.ungleich.ch | cache+auth |
| d2 | router2.place5 | dns2.ungleich.ch | cache+auth |
| d3 | router1.place6 | dns3.ungleich.ch | cache+auth |
| d4 | router2.place6 | dns3.ungleich.ch | cache+auth |
| d5 | server1.place4 | dns1.ungleich.ch | auth |
| d6 | dns6.ungleich.ch | - | auth+synth |
| d7 | dns7.ungleich.ch | - | auth+synth |
h2. How to use the authorative DNS servers in zone files
Add the following to your zone file:
<pre>
; server1.place4
IN NS dns1.ungleich.ch.
; vrrp active router @ place5
IN NS dns2.ungleich.ch.
; vrrp active router @ place6
IN NS dns3.ungleich.ch.
</pre>
h2. DNS64 at datacenterlight/ipv6onlyhosting
"NAT64":https://en.wikipedia.org/wiki/NAT64 allows ipv6-only nodes to reach the v4 world, and requires DNS64 at ungleich.
h3. DNS64 resolvers
DNS64 is usually provided by BIND (d{1..7}.ungleich.ch) depending on the address/prefix emitting the request (see `type/__ungleich_dns_server` in dot-cdist). It can also be provided by the unbound servers of place6 (unbound{1,2}.place6.ungleich.ch), which unconditionally serve DNS64.
h3. Customer VMS
The production infrastructure for DCL/V6OnlyHosting runs at place6 and networks are assigned as follow:
* IPv6Only VMs are assigned to the `place6-ipv6-nat64` OpenNebula network.
* Dual-stack VM are assigned to the `place6-ipv4` and `place6-ipv6`
The `place6-ipv6-nat64` networks *provides NAT64* but the `place6-ipv6` *does not*: we do not want ipv4-capable VMs to be NAT'ed behind NAT64. Due to *legacy reasons*, some ipv6only VMs are in `place6-ipv6` but have NAT64 due to hardcoded per-ip configuration our bind DNS server (see `type/__ungleich_dns_server` type in dot-cdist).
h4. place6-ipv6-with-ip-spoofing
This OpenNebula network is used to routes v6 prefixes (/64, /56, /48) to customer VMs and is shared by Ipv6-Only and Dual-Stack VMs: NAT64 is *disabled* on this network. IPv6-Only customers on this network *MUST* use unbound1.place6.ungleich.ch and unbound2.place6.ungleich.ch as name server. Their `/etc/resolve.conf` file should look like:
<pre>
nameserver 2a0a:e5c0:2:12:0:f0ff:fea9:c451
nameserver 2a0a:e5c0:2:12:0:f0ff:fea9:c45d
</pre>
h3. DNS64 in Ungleich IPv6 VPN
Using ungleich's DNS64 resolvers also allows to route all traffic via the ungleich VPN when enabled. You'll find more details on the [[Ungleich IPv6 wireguard VPN]] page.
h2. Monitoring
The unbound DNS64 resolvers are monitored by our prometheus blackbox exporter (see `type/__dcl_monitoring_server` in dot-cdist).