constellation-server-1.1.0 is not a library.

Constellation

Pluggable authoritative DNS server. Entries can be added & removed from an HTTP REST API.

Constellation is a small authoritative server that lets you manage DNS entries from an HTTP REST API, in a generic way. It can be plugged to your existing infrastructure to manage DNS records for users of your service, eg. to configure outbound email records that cannot be easily wildcarded in a traditional DNS server (DKIM, DMARC, SPF records).

DNS entries are stored in Redis. The DNS database can thus be easily modified and dumped for backup purposes.

Constellation

Who uses it?

👋 You use Constellation and you want to be listed there? Contact me.

Features

Current features

Pluggable authoritative DNS server, comes handy if you need to generate eg. email sub-domains for your users (with DKIM, DMARC and SPF records).
HTTP REST API to check, read, insert, modify and delete DNS records on the fly.
Persistence layer in Redis. This means you can run multiple Constellations hitting against the same database on the network. You can even shard Redis if you need fault tolerance on the DNS data store.

Planned features

DNSSEC support.
Geo-DNS routing support, enabling Constellation to act as a geographic load balancer.

How to use it?

Installation

Constellation is built in Rust. To install it, either download a version from the Constellation releases page, use cargo install or pull the source code from master.

Install from source:

If you pulled the source code from Git, you can build it using cargo:

cargo build --release

You can find the built binaries in the ./target/release directory.

Install from Cargo:

You can install Constellation directly with cargo install:

cargo install constellation-server

Ensure that your $PATH is properly configured to source the Crates binaries, and then run Constellation using the constellation command.

Configuration

Use the sample config.cfg configuration file and adjust it to your own environment.

Available configuration options are commented below, with allowed values:

[server]

log_level (type: string, allowed: debug, info, warn, error, default: warn) — Verbosity of logging, set it to error in production

[dns]

inets (type: array[string], allowed: IPs + ports, default: [0.0.0.0:53, [::]:53]) — Hosts and UDP/TCP ports the DNS server should listen on
tcp_timeout (type: integer, allowed: seconds, default: 2) — Timeout of DNS over TCP connections
nameservers (type: array[string], allowed: domain names, default: no default) — Name server domains for all served domains
soa_master (type: string, allowed: domain names, default: no default) — SOA master domain for all zones served by this name server (name of primary NS server)
soa_responsible (type: string, allowed: email addresses as domain names, default: no default) — SOA responsible email for all zones served by this name server
soa_refresh (type: integer, allowed: seconds, default: 10000) — SOA record refresh value
soa_retry (type: integer, allowed: seconds, default: 2400) — SOA record retry value
soa_expire (type: integer, allowed: seconds, default: 604800) — SOA record expire value
soa_ttl (type: integer, allowed: seconds, default: 3600) — SOA record TTL value
record_ttl (type: integer, allowed: seconds, default: 3600) — DNS records TTL value

[[dns.zone.'{name}']]

Specify your zone name eg. as: [[dns.zone.'crisp.email']] for zone base: crisp.email.

[http]

inet (type: string, allowed: IPv4 / IPv6 + port, default: [::1]:8080) — Host and TCP port the HTTP API server should listen on
workers (type: integer, allowed: any number, default: 2) — Number of workers for the HTTP API server to run on
record_token (type: string, allowed: secret token, default: no default) — Record secret token for management API access (ie. secret password)

[redis]

host (type: string, allowed: hostname, IPv4, IPv6, default: localhost) — Target Redis host
port (type: integer, allowed: TCP port, default: 6379) — Target Redis TCP port
password (type: string, allowed: password values, default: none) — Redis password (if no password, dont set this key)
database (type: integer, allowed: 0 to 255, default: 0) — Target Redis database
pool_size (type: integer, allowed: 0 to (2^32)-1, default: 8) — Redis connection pool size
max_lifetime_seconds (type: integer, allowed: seconds, default: 20) — Maximum lifetime of a connection to Redis (you want it below 5 minutes, as this affects the reconnect delay to Redis if a connection breaks)
idle_timeout_seconds (type: integer, allowed: seconds, default: 600) — Timeout of idle/dead pool connections to Redis
connection_timeout_seconds (type: integer, allowed: seconds, default: 5) — Timeout in seconds to consider Redis dead and reject DNS and HTTP API queries

Run Constellation

Constellation can be run as such:

./constellation -c /path/to/config.cfg

DNS records management (HTTP REST API)

To check, read, insert, modify and delete DNS records, you need to use the Constellation HTTP REST API, that listens on the configured http.inet interface from your config.cfg file.

API overview

Endpoint URL:

HTTP http://constellation.local:8080/zone/<zone_name>/record/<record_name>/<record_type>/

Where:

zone_name: The zone name (ie. base domain), eg. crisp.email
record_name: The record name to read or alter (ie. sub-domain or base domain), eg. inbound.@ for the inbound.crisp.email FQDN, or @ for the crisp.email FQDN
record_type: The DNS record type to read or alter for the record_name; either: a, aaaa, cname, mx, txt (open an issue if you need support for another record type)

Request headers:

Add an Authorization header with a Basic authentication where the password is your configured http.record_token.

API routes

Check if a DNS record exists

HTTP HEAD http://constellation.local:8080/zone/<zone_name>/record/<record_name>/<record_type>/

Example request:

HEAD /zone/crisp.email/record/@/mx HTTP/1.1
Authorization: Basic OlJFUExBQ0VfVEhJU19XSVRIX0FfU0VDUkVUX0tFWQ==

Example response:

HTTP/1.1 200 OK

Get a DNS record

HTTP GET http://constellation.local:8080/zone/<zone_name>/record/<record_name>/<record_type>/

Example request:

GET /zone/crisp.email/record/@/mx HTTP/1.1
Authorization: Basic OlJFUExBQ0VfVEhJU19XSVRIX0FfU0VDUkVUX0tFWQ==

Example response:

HTTP/1.1 200 OK
Content-Type: application/json

{"type":"mx","name":"@","ttl":600,"values":["1 inbound.crisp.email","10 inbound-failover.crisp.email"]}

Write a DNS record (or overwrite existing)

HTTP PUT http://constellation.local:8080/zone/<zone_name>/record/<record_name>/<record_type>/

Example request:

PUT /zone/crisp.email/record/@/mx HTTP/1.1
Authorization: Basic OlJFUExBQ0VfVEhJU19XSVRIX0FfU0VDUkVUX0tFWQ==
Content-Type: application/json; charset=utf-8

{"values":["1 inbound.crisp.email","10 inbound-failover.crisp.email"],"ttl":600}

Example response:

HTTP/1.1 200 OK

Delete a DNS record

HTTP DELETE http://constellation.local:8080/zone/<zone_name>/record/<record_name>/<record_type>/

Example request:

DELETE /zone/crisp.email/record/@/mx HTTP/1.1
Authorization: Basic OlJFUExBQ0VfVEhJU19XSVRIX0FfU0VDUkVUX0tFWQ==

Example response:

HTTP/1.1 200 OK

:fire: Report A Vulnerability

If you find a vulnerability in Constellation, you are more than welcome to report it directly to @valeriansaliou by sending an encrypted email to valerian@valeriansaliou.name. Do not report vulnerabilities in public GitHub issues, as they may be exploited by malicious people to target production servers running an unpatched Constellation instance.

:warning: You must encrypt your email using @valeriansaliou GPG public key: :key:valeriansaliou.gpg.pub.asc.

:gift: Based on the severity of the vulnerability, I may offer a $200 (US) bounty to whomever reported it.

constellation-server 1.1.0

Constellation

Who uses it?

Features

Current features

Planned features

How to use it?

Installation

Configuration

Run Constellation

DNS records management (HTTP REST API)

API overview

API routes

Check if a DNS record exists

Get a DNS record

Write a DNS record (or overwrite existing)

Delete a DNS record

:fire: Report A Vulnerability