named-server - DNS Server in Node.js

Named-server (a fork of trevoro/node-named) is a lightweight DNS server written in pure javascript. It has limited support for the DNS spec, but aims to implement all of the common functionality that is in use today.

This fork was created as the original node-named module was not actively maintained anymore. The fork has, until now:

• Added PTR records
• Added method to add Authority and Additional answers to response
• Fixed IPv4 address binding (Error binding to ipv4 interface: EINVAL)
• Fixed bug where an invalid response was being sent if the query had some additional records

Installation

$ npm install named-server

Creating a DNS Server

const named = require('named-server')
const server = named.createServer()
var ttl = 300
 
server.listen(9999, '127.0.0.1', function() {
    console.log('DNS server started on port 9999')
});
 
server.on('query', function(query) {
    var domain = query.name()
    console.log('DNS Query: %s', domain)
 
    var target = new named.SOARecord(domain, {serial: 12345})
    query.addAnswer(domain, target, ttl)
 
    server.send(query)
});

Creating DNS Records

node-named provides helper functions for creating DNS records. The records are available under 'named.record.NAME' where NAME is one of ['A', 'AAAA', 'CNAME', 'PTR', 'SOA', 'MX', 'NS', 'TXT, 'SRV']. It is important to remember that these DNS records are not permanently added to the server. They only exist for the length of the particular request. After that, they are destroyed. This means you have to create your own lookup mechanism.

var named = require('named-server');
 
var soaRecord = new named.SOARecord('example.com', {serial: 201205150000});
console.log(soaRecord);

Supported Record Types

The following record types are supported

• A (ipv4)
• AAAA (ipv6)
• CNAME (aliases)
• PTR (reverse lookups)
• SOA (start of authority)
• MX (mail server records)
• NS (nameserver entries)
• TXT (arbitrary text entries)
• SRV (service discovery)

Logging

node-named uses http://github.com/trentm/node-bunyan for logging. It's a lot nicer to use if you npm install bunyan and put the bunyan tool in your path. Otherwise, you will end up with JSON formatted log output by default.

Replacing the default logger

You can pass in an alternate logger if you wish. If you do not, then it will use bunyan by default. Your logger must expose the functions 'info', 'debug', 'warn', 'trace', 'error', and 'notice'.

TODO

• Better record validation
• Create DNS client for query recursor
• Add support for TCP AXFR requests

Tell me even more...

When DNS was designed it was designed prior to the web existing, so many of the features in the RFC are either never used, or were never implemented. This server aims to be RFC compliant, but does not implement any other protocol other than INET (the one we're all used to), and only supports a handful of record types (the ones that are in use on a regular basis).

Looking up Records

There are a few handy ways to lookup DNS records in node. https://github.com/LCMApps/dns-lookup-cache