Erlang DNS Server
View SourceServe DNS authoritative responses... with Erlang.
This application consists of three main subsystems:
erldns_zones
The system responsible for loading and caching zone data.erldns_pipeline
The system responsible for processing incoming DNS queries.erldns_listeners
The system responsible for listening for incoming DNS queries. The system is designed to be able to listen on multiple ports and interfaces and supports both UDP and TCP, Unix network stack optimisations, and high parallelism.
There is also an administrative API for querying the current zone cache and for basic control.
You can read more about it at erldns_admin
.
Instrumentation
Telemetry is used to instrument the code.
All events are divided in the following namespaces:
[erldns, pipeline | _]
are triggered by theerldns_pipeline
subsystem.[erldns, request | _]
are triggered by theerldns_listeners
subsystem.
Getting started
You can use this application as a standalone service or embedded into your OTP application. In both cases, you'll need to: configure it, and load zones.
Zones
Zones are loaded from JSON files in the priv/zones/
directory. The path is configured in erldns.config
using the zones.path
setting. For more details about zone file format and configuration, see priv/zones/ZONES
.
Configuration
An example configuration file can be found in erldns.example.config
. For more details, see the
subsystems and the admin API documentation.
To get started, copy it into your own erldns.config
and modify as needed.
Building
To build:
make
To start fresh:
make fresh
make
Running
Launch directly
overmind start
To get an interactive Erlang REPL
rebar3 shell
Build a distribution with and run the release
rebar3 release
_build/default/rel/erldns/bin/erldns foreground
Querying
Here are some queries to try:
dig -p 8053 @127.0.0.1 example.com a
dig -p 8053 @127.0.0.1 example.com cname
dig -p 8053 @127.0.0.1 example.com ns
dig -p 8053 @127.0.0.1 example.com mx
dig -p 8053 @127.0.0.1 example.com spf
dig -p 8053 @127.0.0.1 example.com txt
dig -p 8053 @127.0.0.1 example.com sshfp
dig -p 8053 @127.0.0.1 example.com soa
dig -p 8053 @127.0.0.1 example.com naptr
dig -p 8053 @127.0.0.1 -x 127.0.0.1 ptr
Performance
If you want to perform some benchmarks, see benchmarking
.
AXFR Support
AXFR zone transfers are not currently implemented. The current "implementation" is just a stub.
Tests
To run automated tests:
make test
This runs the following: